New Circuits Page 214
- Page 214
-
This circuit was designed to obtain a valve-like distorted sound from an electric guitar or other musical instrument.
For this purpose a very high gain, three-FET amplifier circuit, was used. The output square wave shows marked rounded corners, typical of....
-
-
When activated by pressing a button, this time delay relay will activate a load after a specified amount of time. This time is adjustable to whatever you want simply by changing the value of a resistor and/or capacitor. The current capacity of the circuit is....
-
This Design Idea stems from the limited availability of IC voltage regulators that can meet key USB-power specs, coupled with the need for turn-on sequencing and rise-time control at each output. As always, for PC-related designs, minimum cost is a primary....
-
This circuit uses a PUT for phases control of an SCR. The relaxation oscillator formed by Q2 provides conduction control of Ql from 1 to 7.8 ms or 21.6° to 168.5°. This constitutes control of over 97% of the power available to the load. ..
-
The IC has an FLL (frequency-locked-loop) structure. The filtered output of the FM discriminator frequency-modulates the local oscillator to provide negative-feedback modulation. The result is compression of the signal at the output of the mixer. Thus, the....
-
The ping of the cymbals, crack of the snare drum, thonk of the bass - none of these comes through on my low-budget speakers. Sometimes they sound so fuzzy I want to hide behind the couch until it’s over. But headphones...ah, heaven! There are probably as....
-
-
This is a new design for a universal gear indicator that can be fitted to any motorcycle as an aftermarket accessory. Its main advantage is that its operation depends entirely on the gear shift lever movement, instead of connecting to speedometer and....
-
Switch on one unit, and everything else you need turns on automatically. This can save the tedium of turning on half a dozen different things, when one should be enough! This is another project created purely from necessity. In my case, it was to switch....
-
The principle of operation is quite simple, a counter measures the VFO frequency, the new
reading is compared with the previously stored value and an adequate correction is applied
consequently. This process has been implemented in the past using several....
-
Here is an inexpensive way to get slow-moving analog data directly into a spreadsheet on your computer! A simple circuit connects to a serial port and a short Qbasic program gathers and saves 12 bit data to a file. A spreadsheet automatically retrieves the....
-
A simple inventer and NAND gate can be connected to yield a highly compact and reliable digital frequency detector. This circuit can detect frequencies up to 3 MHz with 50% duty cycles. When a frequency, j,, appears at the input, points A and B detect a....
-
-
A single chip metal detecor with a range of a few inches. This is useful for decting nails or screws in walls and floors, or for locating buried mains cable. The heart of the circuit is a single IC the CS209A made by Cherry Semiconductor. The detector, is a....
-
This simple micro-control circuit controls a servo motor according to a 3-state switch. A servo motor acts as an actuator in 3 position. It has 3 wires, one for VCC, one for Ground and another one for position control. The last signal is a single pulse with....
-
The battery tester uses four transistors and two LEDs to indicate the condition of any battery you want to test. Q3 and Q4 are connected in a Darlington configuration that has extremely high gain. LED L2 lights when a small positive potential appears on the....
-
Like most other ESCs, this one is built up using N-channel Power MOSFET`s because of their good characteristics (low DS resistance). Since this ESC has no reverse, it is not meant to be used in R/C cars or boats if reversed motor run is needed. It is more....
-
Here is a design for a DC motor speed control featuring: Efficient PWM H-bridge MOSFET architecture. Supply (battery) voltage range from 4.2 to 13 volts. High current capacity for driving large motors (65 amps max). Input compatible with standard RC hobby....
-
When the time delay expires, SCRl conducts and removes the gate signal from SCR2, which stops the motor. Both the time delay and motor speed are adjustable by potentiometers R2 and R3. If heavier motor loads are anticipated, use the larger C30B SCR in place....
-
A high voltage power supply is a very useful source which can be effectively used in many applications like biasing of gas-discharge tubes and radiation detectors etc. Such a power supply could also be used for protection of property by electric charging of....
-
An outside horn-type speaker works best with the circuit. However, such devices require a great deal of power, so this sounder should only be used in alarm circuits where at least a 6-A SCR is used as the sounder driver. A single CMOS 4001 quad 2-input NOR....
-
The main requirement for efficient de restoration is to provide a short time-constant during the clamp period, with a long time-constantlluring the active line time. The switch within the Harris HI201HS has an on resistance of 30 0 and the PM! buffer,....
-
There are two ways to program AVR-P40-USB:
with ICSP port and with JTAG port.
To program via ICSP port you need serial port or
parallel port AVR-ICSP programmer dongle
(Olimex part # AVR-PG1B or AVR-PG2B).
The serial port ICSP programmer (AVR-PG1B)....
-
The CD4060 is a CMOS 14-stage binary counter with an internal oscillator on chip. The oscillator is controlled by the resistors and capacitor tied to the timing pins, 9-11. This oscillator runs the binary counter, and the various outputs count at the....
-
This Mini FM Bug Detector is basically a broad-band receiver. It picks up the complete band from below 80Mhz to 150MHz and almost anything that transmits in that band will be detected. If a bug with a sensitive microphone is transmitting nearby, the result....
-
This circuit for a compressor uses a high-fidelity external op amp, and a high gain and wide bandwidth. A compensation network input is necessary for stability. The rectifier capacitor (Cg) is not grounded. but it is linked to the output of an op amp....
-
The phono preamp shown has an accurate RIAA equalisation curve, is very quiet, and offers far better sonic performance than the vast majority of those seen in magazines and application notes. Like most other ESP projects, it is very tolerant of opamps but....
-
I have received a few emails asking for a transformerless power supply. Here is such a supply. This supply uses no heavy step down transformer and has an extremely low parts count. The circuit can be built very small and can supply small currents for small....
-
In the circuit of Figure 1, assume that a brush-type dc motor must drive a load back and forth between two endpoints on a lead screw. Optical sensors determine end of travel, and an SPDT switch selects to which end to send the load. The sensors themselves....
-
The circuit can be used to tell whether or not an input signal is within a certain frequency range. The device consists of three !Cs, a dual monostable multivibrator, and two dual D-type flip-flops. The signal whose frequency is in question is fed to the....
-
This simple circuit has helped me out on many occasions. It is able to check transistors, in the circuit, down to 40 ohms across the collector-base or base-emitter junctions. It can also check the output power transistors on amplifier circuits. Circuit....
-
The convenience of selecting TV channels using your remote and then pointing the same remote to your Computer so that you can control the whole system using the single remote control. The Following functions can be done with PC Remote control...
-
The circuit uses two CMOS IC’s
IC1 uses inverters connected as a Colpitts oscillator of 100KHz; the LC frequency determining elements being the search coil and parallel resonating capacitor.
An 80 turn close wound 30swg 100mm diameter coil will fit inside....
-
Only one channel of this circuit is shown. The other is practically a carbon copy.The input to the circuit, taken from your car radio`s speaker output, is divided along two paths; in one path, a high-power divider network (consisting of R8 through R10)....
-
This circuit can be used to operate a VCR or CD player from another room. It"s really an infrared signal repeater. The s..
-
This circuit (figure 1) will impose a maximum slew rate on a signal; positive and negative rates can be independently controlled. The circuit is useful in servo applications where the error signal needs to be limited to be within the power rails to ensure....
-
Figure A is an R/2R resistor ladder. Each switch that is closed increases the amount of current at . A simple channel A/D converter is shown in Fig. B. The voltage reference (D2) is common to all channels, but-the value of the dropping resistor (R9) varies....
-
My first project after assembling an electronic design lab was to build a flash trigger that I could use for high-speed photography. I thought it would be useful to share not only the finished product but also the reasoning that went into its design — in the....
-
When the fan seized up in my source and I changed it to a type with much less noise, turned on my computer, the largest source of noise CPU cooler fan. The computer I have a boxed Pentium III processor in slot 1, which is practically dismountable and fan....
-
That Circuit is an advanced bicycle lighting system which will power your lights and also charge four NiCd batteries while you running in the streets, for keeping the lights on while the bicycle is stoped. Its fully automated without any switches. ..
-
This circuit is suitable for fitting into slide projectors without a dimmer facility as witb 24-Vac fed halogen lamps. With a few small alterations, it can also be used for dimming 12-V halogen lamps, but not those in a car, because these are fed from a de....
-
This simple diode modulator delivers excellent results when used for high percentage modulation at low signal levels. Constants are shown for a carrier frequency of about 10 MHz, but, with a suitable tank, the circuit will give good results at any frequency....
-
The voltage reference circuit described below, is a special implementation of current source LM334. Characterized by a very small temperature coefficient metatholio output voltage and consumes only 10uA room temperature. This current fluctuates by a few uA,....
-
A continuously working wiper in a car may prove to be a nuisance, especially when it is not raining heavily. By using the circuit described here one can vary sweeping rate of the wiper from once a second to once in ten seconds. The circuit comprises two....
-
Rechargeable lithium-ion batteries are rapidly becoming
the battery of choice for many battery-powered products.
These products include notebook computers, PDAs, video
camcorders, digital cameras, cellular phones, portable
test equipment and others.....
-
The charger consists of two stages: The first is a capacitive voltage doubler, which uses a 555 timer IC driving a pair of transistors connected as emitter followers, which in turn drive the voltage doubler proper. The doubler has power resistors built in,....
-
The supply receives -20 V from the rectifier/filter which is fed to the collector of the Darlington pnp pass transistor, a TIP105. The base drive to the TIP105 is supplied through resistor R5. The base of the TIP is driven from Vz terminal at pin 9, which is....
-
This circuit was designed to provide a valuable test equipment tool for sound reinforcement systems like guitar amplifiers and the like. Used in conjunction with a signal generator it can be of considerable help in setting and controlling levels through any....
-
This system uses a transmitter at around 100 kHz (see Fig. 86-3(a)) to control a remote rece..
-
Capacitor Cl is connected continuously through the supply of 3 volts to 10 megohm resistor Rl. The capacitor is charged (relatively slowly) to 3 volts. The wink SWI is closed, it connects the charged capacitor (Cl) in series with C2 and R2. The capacitor C2....
-
This circuit can be used to construct an attractive Christmas Star. When we switch on this circuit, the brightness of lamp L1 gradually increases. When it reaches the maximum brightness level, the brightness starts decreasing gradually. And when it reaches....
-
Fixed-value capacitors are disc ceramics. CI, C4, C5, C6, and C8 are NPO ceramic or polystyrene. C2 is a 25-pF ceramic trimmer and C3 is a 15- pF miniature air variable capacitor. The resistors are -W carbon film or composition. The RF chokes are miniature....
-
The three best known of these signals are the DCF77 signal broadcast from Mainflingen near Frankfurt in Germany on 77.5kHz which can be received through out most of central and northern europe. The MSF signal broadcast from outside Rugby in England by the....
-
The clock will have 6 digits and time setting will be done by means of a few buttons. I will try to use the most common types from widely used microcontroller families of miscellaneous producers. I will write the program in C language. Nixies need high....
-
The LTC®1440 series comparators are true micropower
devices. They eliminate current peaking during switching,
resulting in greatly reduced power consumption versus
frequency, or when the inputs are nearly balanced. Figure
2s plot contrasts the LTC1440s....
-
To maintain an alarm condition when an overvoltage transient disappears, add an SCR to the comparator circuits. For SCR operation, voltages to the comparator inputs are inverted. (B) The triple-voltage monitoring circuit detects transient power-supply....
-
The circuit uses easily available components. Most of the coils are wound on low cost balun core. The circuit uses ladder filter. Filter is build around four numbers of 4.43 MHz crystals. I used ladder filter because it is cheap and getting reasonably good....
-
This project uses an LM3915 bar-graph IC driving two sets of ten LEDs for a 30dB range. The circuit is unique because it has an additional range of 20dB provided by an automatic gain control to allow it to be very sensitive to low sound levels but it....
-
A large number of intercom stations can be tied together. All units are connected in parallel, and the entire system is buzzed by only one signaling circuit. Each unit is powered individually from 1.5-V cells for redundancy. For greater signal volume, 3-V....
-
Moreover, the method does not entail programming and the concomitant, almost inevitable, debugging. A CD4016 CMOS analog switch, IC1, forms the heart of the system. Depressing the key labeled "1st" closes the topmost switch (between pins 1 and 2), which....
-
The resistor between basis and collector (around 47k) is to be individually set according transistor characteristics. Without PIC in socket at the collector should be 2.5 V...
-
A wide rage auto turn OFF timer covering 1 minute to 20 hours in three ranges with S1. As soon as power is applied to the circuit the IC1 [555] starts to oscillate happily and feeds clock pulses to the IC2 [4017]. The IC2 [4017] and IC3 [4020] give a....
-
Some applications, such as driving three-state buffers for data multiplexers or for biphase clocks in high-speed systems, require complementary signals having a small-time skew and nearly simultaneous transitions. Here, XOR gates function as both....
-
The ICM7216A or can be used as a minimum component complete Universal Counter. This circuit can use input frequencies up to 10 MHz at INPUT A and 2 MHz at INPUT B. If the signal at INPUT A has a very low duty cycle it may be necessary to use a 74121....
-
The circuit is built around the IR2520D Ballast Control IC. The IR2520D provides adjustable preheat time,
adjustable run frequency to set the lamp power, high starting frequency for soft start and to avoid lamp flash,
fault protection for open filament....
-
An IBM PC can operate the two 12-bit A/D converters in Fig. 1 via its printer port. The converters" serial outputs use only two o..
-
A Class A // Class AB amplifier rated 100 Watts when driving a 4 ohm loudspeaker. This circuit developed out of my 30+ years of JLH class-A based investigations.
The original `simple` 1969 JLH class-A design provided excellent first cycle accuracy....
-
This circuit is a mono audio amplifier that will boost low frequencies as you see at the frequency response. The circuit is suitable for driving a subwoofer speaker for example. The output power of the circuit is about 1 Watt with a 4-ohm speaker. ..
-
This system operates on the principle that capacitance loading of an oscillator will lower its frequency. When a foreign body comes into contact with touch plate, the frequency of Ul is lowered...
-
Most operational amplifier circuits require a dual-polarity power supply - one having +V and -V. However, there are times when a DP supply simply isn't conveniently available. Single-polarity modifications to DP designs often acheive their effect by....
-
This little tester is useful for checking vehicle electrical circuits. Two LEDs indicate whether one of the cl..
-
This interface circuit provides electrically isolated RS422 communication interface to the PC serial port the isolation circuit protect the PC from direct connection to hazardous voltages...
-
In solar cell array applications and solar instrumentation, it is desirable to monitor the approximate position of the sun to allow efficient automatic alignment. The Ll4Gllens can provide about 15° of accuracy in a simple level sensing circuit, and a....
-
The battery low-voltage detector uses a CD4093 Schmitt trigger and a capacitor that acts as a 1-bit dynamic RAM. The c..
-
This circuit uses a TBA820 audio 1C to amplify underwater sounds. The microphone must be waterproofed. This project was originally used in a home aquarium to monitor fish sounds...
-
A power MOSFET and a quad exclusive-OR oscillator makes an effective solid-state relay. Figure 75-5(a)"s capacitively iso..
-
Examples of RF and audio ANL circuits. Positive and negative clipping occurs in both circuits. The circuit at A i..
-
The circuit uses the LTC1043 in a variable gain amplifier which features continuously variable gain, gain stability of 20 ppm/°C, and single-ended or differential inputs. The circuit uses two separate LTC1043s. LTC1043B is continuously clocked by a....
-
The resulting timer circuit is made from a CD4060, includes an oscillator and a 14 stage binary counter, two CD4040's, which are 12 stage binary counters, a CD4012 Dual Nand gate and a CD4013 Dual D Latch. The CD4060 is connected to a 32768 Hz ECS 3X8....
-
The circuit operates from a 5-V supply arid has a current consumption of 2 mA. The output is a current source that drives or suppresses a current of more than 75 with a voltage swing of 4.5 V. The Q-killer circuit eliminates distortion of the output pulses....
-
The sunset lamp comes on at full brightness and then slowly fades out over 1.5 hours time and stays off until power is recycled...
-
Using only 2 capacitors, 3 resistors, 4 seven-segment Display, 1 xtal, 2 switches n.o. and 1 Microcontroller PIC, you can build this Digital Led Clock. you can use common anode or common cathode display, just select the display type. Here is the pinout....
-
This preamplifier was designed to cope with CD players, tuners, tape recorders etc., providing a gain of 4, in order to drive less sensitive power amplifiers. As modern Hi-Fi home equipment is frequently fitted with small loudspeaker cabinets, the bass....
-
An NE567 tone decoder, tuned to the transceiver"s CW offset frequency, ensures that the transceiver will be tran..
-
By vocalizing the numbers and symbols of its~eypad, the phone provides an audible confirmation that is useful to the blind. The serial-interface, 2 K-byte x 8-bit ROM (!C4) stores programmed sequences of instructions that are executed by the....
-
The circuit will provide 3 preset currents which will remain constant despite variations of ambient temperature or line voltage. ZDl produces-a temperature stable reference voltage which is applied to the noninverting input of ICl. 100% feedback is applied....
-
The circuit is powered by the receiver's pack, the current drain is low, specially if compared to drain of servos.
U1a VZ2 and Q1 are the CURRENT source of the sensor VZ2 is temperature compensated, use the listed component except for Q1 there you can use....
-
The dc voltage present on a telephone line is usually around 45 to 50 V on-hook and 6 V off-hook. This circuit uses This drop in voltage to activate a relay. The relay controls a cassette tapeTecorder...
-
This was my first sucessful project with a PIC chip. I used a 16F84 with a 10MHz resonator with built in caps. Click here to view the source code to this project. The code is written in Hi-Tech C. Click here to download the source code to this project. File....
-
The circuit draws so little current that the shelf-line of the battery is the limiting factor. The only current drawn is the leakage of the transistor. The circuit is shown in the form of a water level alarm but by using different forms of probe can act as a....
-
This monitor uses a common 7 41 amp configured as a comparator and a low cost nontransistor as an output driver. With no liquid detected, a voltage of about 2. 92 V is present in the op amp"s inverting input at pin 2. The 100-KO resistors establish a....
-
Ql and Q2 switch the primary windings of transformer Tl via a square wave at a frequency determined by its magnetic properties. Diodes Dl and D2 provide base return paths for the feedback current of Ql and Q2. The output winding of T1 is connected to a....
-
This general purpose signal source serves very well in signal-tracing applications. The output level is variable to more than 1 Vrms into a 50 O load. Almost any crystal in the 1 to 15 MHz range can be used. Ql forms a Colpitis oscillator with the output....
-
This project is designed to program the 8-pin PIC12c508A and 18pin PIC16F84 microcontroller chips to support the projects we have designed, however it will also program a number of other 8-pin & 18-pin microcontrollers and the full list can be seen when....
-
The circuit uses Ql to buffer the right-channel balance output while Q2 and Q3 form a VOX circuit. When the signal level from the microphone goes high, the output of the VOX also goes high and the multiplexer inside IC1 switches the high-gain left-channel....
-
The circuit diagram of the Lie Detector is shown above. It consists of three transistors (TR1 to TR3), a capacitor (C1), two lights or LEDs (L1 & L2), five resistors (R1 to R5), and a variable resistor (VR1).
This circuit is based on the fact that a....
-
This circuit does not require an output transformer or an output coupling capacitor; the annunciator can easily be turned on or off by a control input voltage driving a 10Mohm input resistor, R3. For a smaller acoustic output, replace output transistor Ql,....
-
Relay K1 has a low-impedance coil and K2 has a high-impedance coil. When a sensor opens, current is routed throu..
-
This is probably one of the most legendary fuzz pedals that has ever existed, and for good reason too! This thing can produce some completely saturated fuzz that is capable of slipping into feedback easily if you crank it up loud enough. I just can't say....
-
This waveshape generator is basically a slow running oscillator with variable attack and decay. A variable amplitude (high impedance) output is available via the 2M potentiometer. B shows an add-on circuit which should be used if a low impedance output is....
-
Filtered 15 V de is applied to a series circuit consisting of thermistor R2 and parallel combination of resistors Rl and R3. Transistor Ql acts as a switch whose state is determined by the setting of potentiometer R3, which is first set so just enough....
-
This circuit provides on/off switching, soft starting, current monitoring, current tripping, and protection against overcurrent for a 30 Vdc power supply at normal load currents up to 2 A. The switch is turned on by an "on" command pulse; it is turned off by....
This circuit was designed to obtain a valve-like distorted sound from an electric guitar or other musical instrument. For this purpose a very high gain, three-FET amplifier circuit, was used. The output square wave shows marked rounded corners, typical of....
When activated by pressing a button, this time delay relay will activate a load after a specified amount of time. This time is adjustable to whatever you want simply by changing the value of a resistor and/or capacitor. The current capacity of the circuit is....
This Design Idea stems from the limited availability of IC voltage regulators that can meet key USB-power specs, coupled with the need for turn-on sequencing and rise-time control at each output. As always, for PC-related designs, minimum cost is a primary....
This circuit uses a PUT for phases control of an SCR. The relaxation oscillator formed by Q2 provides conduction control of Ql from 1 to 7.8 ms or 21.6° to 168.5°. This constitutes control of over 97% of the power available to the load. ..
The IC has an FLL (frequency-locked-loop) structure. The filtered output of the FM discriminator frequency-modulates the local oscillator to provide negative-feedback modulation. The result is compression of the signal at the output of the mixer. Thus, the....
The ping of the cymbals, crack of the snare drum, thonk of the bass - none of these comes through on my low-budget speakers. Sometimes they sound so fuzzy I want to hide behind the couch until it’s over. But headphones...ah, heaven! There are probably as....
This is a new design for a universal gear indicator that can be fitted to any motorcycle as an aftermarket accessory. Its main advantage is that its operation depends entirely on the gear shift lever movement, instead of connecting to speedometer and....
Switch on one unit, and everything else you need turns on automatically. This can save the tedium of turning on half a dozen different things, when one should be enough! This is another project created purely from necessity. In my case, it was to switch....
The principle of operation is quite simple, a counter measures the VFO frequency, the new reading is compared with the previously stored value and an adequate correction is applied consequently. This process has been implemented in the past using several....
Here is an inexpensive way to get slow-moving analog data directly into a spreadsheet on your computer! A simple circuit connects to a serial port and a short Qbasic program gathers and saves 12 bit data to a file. A spreadsheet automatically retrieves the....
A simple inventer and NAND gate can be connected to yield a highly compact and reliable digital frequency detector. This circuit can detect frequencies up to 3 MHz with 50% duty cycles. When a frequency, j,, appears at the input, points A and B detect a....
A single chip metal detecor with a range of a few inches. This is useful for decting nails or screws in walls and floors, or for locating buried mains cable. The heart of the circuit is a single IC the CS209A made by Cherry Semiconductor. The detector, is a....
This simple micro-control circuit controls a servo motor according to a 3-state switch. A servo motor acts as an actuator in 3 position. It has 3 wires, one for VCC, one for Ground and another one for position control. The last signal is a single pulse with....
The battery tester uses four transistors and two LEDs to indicate the condition of any battery you want to test. Q3 and Q4 are connected in a Darlington configuration that has extremely high gain. LED L2 lights when a small positive potential appears on the....
Like most other ESCs, this one is built up using N-channel Power MOSFET`s because of their good characteristics (low DS resistance). Since this ESC has no reverse, it is not meant to be used in R/C cars or boats if reversed motor run is needed. It is more....
Here is a design for a DC motor speed control featuring: Efficient PWM H-bridge MOSFET architecture. Supply (battery) voltage range from 4.2 to 13 volts. High current capacity for driving large motors (65 amps max). Input compatible with standard RC hobby....
When the time delay expires, SCRl conducts and removes the gate signal from SCR2, which stops the motor. Both the time delay and motor speed are adjustable by potentiometers R2 and R3. If heavier motor loads are anticipated, use the larger C30B SCR in place....
A high voltage power supply is a very useful source which can be effectively used in many applications like biasing of gas-discharge tubes and radiation detectors etc. Such a power supply could also be used for protection of property by electric charging of....
An outside horn-type speaker works best with the circuit. However, such devices require a great deal of power, so this sounder should only be used in alarm circuits where at least a 6-A SCR is used as the sounder driver. A single CMOS 4001 quad 2-input NOR....
The main requirement for efficient de restoration is to provide a short time-constant during the clamp period, with a long time-constantlluring the active line time. The switch within the Harris HI201HS has an on resistance of 30 0 and the PM! buffer,....
There are two ways to program AVR-P40-USB: with ICSP port and with JTAG port. To program via ICSP port you need serial port or parallel port AVR-ICSP programmer dongle (Olimex part # AVR-PG1B or AVR-PG2B). The serial port ICSP programmer (AVR-PG1B)....
The CD4060 is a CMOS 14-stage binary counter with an internal oscillator on chip. The oscillator is controlled by the resistors and capacitor tied to the timing pins, 9-11. This oscillator runs the binary counter, and the various outputs count at the....
This Mini FM Bug Detector is basically a broad-band receiver. It picks up the complete band from below 80Mhz to 150MHz and almost anything that transmits in that band will be detected. If a bug with a sensitive microphone is transmitting nearby, the result....
This circuit for a compressor uses a high-fidelity external op amp, and a high gain and wide bandwidth. A compensation network input is necessary for stability. The rectifier capacitor (Cg) is not grounded. but it is linked to the output of an op amp....
The phono preamp shown has an accurate RIAA equalisation curve, is very quiet, and offers far better sonic performance than the vast majority of those seen in magazines and application notes. Like most other ESP projects, it is very tolerant of opamps but....
I have received a few emails asking for a transformerless power supply. Here is such a supply. This supply uses no heavy step down transformer and has an extremely low parts count. The circuit can be built very small and can supply small currents for small....
The circuit can be used to tell whether or not an input signal is within a certain frequency range. The device consists of three !Cs, a dual monostable multivibrator, and two dual D-type flip-flops. The signal whose frequency is in question is fed to the....
This simple circuit has helped me out on many occasions. It is able to check transistors, in the circuit, down to 40 ohms across the collector-base or base-emitter junctions. It can also check the output power transistors on amplifier circuits. Circuit....
The convenience of selecting TV channels using your remote and then pointing the same remote to your Computer so that you can control the whole system using the single remote control. The Following functions can be done with PC Remote control...
The circuit uses two CMOS IC’s IC1 uses inverters connected as a Colpitts oscillator of 100KHz; the LC frequency determining elements being the search coil and parallel resonating capacitor. An 80 turn close wound 30swg 100mm diameter coil will fit inside....
Only one channel of this circuit is shown. The other is practically a carbon copy.The input to the circuit, taken from your car radio`s speaker output, is divided along two paths; in one path, a high-power divider network (consisting of R8 through R10)....
This circuit can be used to operate a VCR or CD player from another room. It"s really an infrared signal repeater. The s..
This circuit (figure 1) will impose a maximum slew rate on a signal; positive and negative rates can be independently controlled. The circuit is useful in servo applications where the error signal needs to be limited to be within the power rails to ensure....
Figure A is an R/2R resistor ladder. Each switch that is closed increases the amount of current at . A simple channel A/D converter is shown in Fig. B. The voltage reference (D2) is common to all channels, but-the value of the dropping resistor (R9) varies....
My first project after assembling an electronic design lab was to build a flash trigger that I could use for high-speed photography. I thought it would be useful to share not only the finished product but also the reasoning that went into its design — in the....
When the fan seized up in my source and I changed it to a type with much less noise, turned on my computer, the largest source of noise CPU cooler fan. The computer I have a boxed Pentium III processor in slot 1, which is practically dismountable and fan....
That Circuit is an advanced bicycle lighting system which will power your lights and also charge four NiCd batteries while you running in the streets, for keeping the lights on while the bicycle is stoped. Its fully automated without any switches. ..
This circuit is suitable for fitting into slide projectors without a dimmer facility as witb 24-Vac fed halogen lamps. With a few small alterations, it can also be used for dimming 12-V halogen lamps, but not those in a car, because these are fed from a de....
This simple diode modulator delivers excellent results when used for high percentage modulation at low signal levels. Constants are shown for a carrier frequency of about 10 MHz, but, with a suitable tank, the circuit will give good results at any frequency....
The voltage reference circuit described below, is a special implementation of current source LM334. Characterized by a very small temperature coefficient metatholio output voltage and consumes only 10uA room temperature. This current fluctuates by a few uA,....
A continuously working wiper in a car may prove to be a nuisance, especially when it is not raining heavily. By using the circuit described here one can vary sweeping rate of the wiper from once a second to once in ten seconds. The circuit comprises two....
The charger consists of two stages: The first is a capacitive voltage doubler, which uses a 555 timer IC driving a pair of transistors connected as emitter followers, which in turn drive the voltage doubler proper. The doubler has power resistors built in,....
The supply receives -20 V from the rectifier/filter which is fed to the collector of the Darlington pnp pass transistor, a TIP105. The base drive to the TIP105 is supplied through resistor R5. The base of the TIP is driven from Vz terminal at pin 9, which is....
This circuit was designed to provide a valuable test equipment tool for sound reinforcement systems like guitar amplifiers and the like. Used in conjunction with a signal generator it can be of considerable help in setting and controlling levels through any....
This system uses a transmitter at around 100 kHz (see Fig. 86-3(a)) to control a remote rece..
Capacitor Cl is connected continuously through the supply of 3 volts to 10 megohm resistor Rl. The capacitor is charged (relatively slowly) to 3 volts. The wink SWI is closed, it connects the charged capacitor (Cl) in series with C2 and R2. The capacitor C2....
This circuit can be used to construct an attractive Christmas Star. When we switch on this circuit, the brightness of lamp L1 gradually increases. When it reaches the maximum brightness level, the brightness starts decreasing gradually. And when it reaches....
Fixed-value capacitors are disc ceramics. CI, C4, C5, C6, and C8 are NPO ceramic or polystyrene. C2 is a 25-pF ceramic trimmer and C3 is a 15- pF miniature air variable capacitor. The resistors are -W carbon film or composition. The RF chokes are miniature....
The three best known of these signals are the DCF77 signal broadcast from Mainflingen near Frankfurt in Germany on 77.5kHz which can be received through out most of central and northern europe. The MSF signal broadcast from outside Rugby in England by the....
The clock will have 6 digits and time setting will be done by means of a few buttons. I will try to use the most common types from widely used microcontroller families of miscellaneous producers. I will write the program in C language. Nixies need high....
To maintain an alarm condition when an overvoltage transient disappears, add an SCR to the comparator circuits. For SCR operation, voltages to the comparator inputs are inverted. (B) The triple-voltage monitoring circuit detects transient power-supply....
This project uses an LM3915 bar-graph IC driving two sets of ten LEDs for a 30dB range. The circuit is unique because it has an additional range of 20dB provided by an automatic gain control to allow it to be very sensitive to low sound levels but it....
A large number of intercom stations can be tied together. All units are connected in parallel, and the entire system is buzzed by only one signaling circuit. Each unit is powered individually from 1.5-V cells for redundancy. For greater signal volume, 3-V....
The resistor between basis and collector (around 47k) is to be individually set according transistor characteristics. Without PIC in socket at the collector should be 2.5 V...
A wide rage auto turn OFF timer covering 1 minute to 20 hours in three ranges with S1. As soon as power is applied to the circuit the IC1 [555] starts to oscillate happily and feeds clock pulses to the IC2 [4017]. The IC2 [4017] and IC3 [4020] give a....
Some applications, such as driving three-state buffers for data multiplexers or for biphase clocks in high-speed systems, require complementary signals having a small-time skew and nearly simultaneous transitions. Here, XOR gates function as both....
The ICM7216A or can be used as a minimum component complete Universal Counter. This circuit can use input frequencies up to 10 MHz at INPUT A and 2 MHz at INPUT B. If the signal at INPUT A has a very low duty cycle it may be necessary to use a 74121....
The circuit is built around the IR2520D Ballast Control IC. The IR2520D provides adjustable preheat time, adjustable run frequency to set the lamp power, high starting frequency for soft start and to avoid lamp flash, fault protection for open filament....
An IBM PC can operate the two 12-bit A/D converters in Fig. 1 via its printer port. The converters" serial outputs use only two o..
A Class A // Class AB amplifier rated 100 Watts when driving a 4 ohm loudspeaker. This circuit developed out of my 30+ years of JLH class-A based investigations. The original `simple` 1969 JLH class-A design provided excellent first cycle accuracy....
This circuit is a mono audio amplifier that will boost low frequencies as you see at the frequency response. The circuit is suitable for driving a subwoofer speaker for example. The output power of the circuit is about 1 Watt with a 4-ohm speaker. ..
This system operates on the principle that capacitance loading of an oscillator will lower its frequency. When a foreign body comes into contact with touch plate, the frequency of Ul is lowered...
Most operational amplifier circuits require a dual-polarity power supply - one having +V and -V. However, there are times when a DP supply simply isn't conveniently available. Single-polarity modifications to DP designs often acheive their effect by....
This little tester is useful for checking vehicle electrical circuits. Two LEDs indicate whether one of the cl..
This interface circuit provides electrically isolated RS422 communication interface to the PC serial port the isolation circuit protect the PC from direct connection to hazardous voltages...
In solar cell array applications and solar instrumentation, it is desirable to monitor the approximate position of the sun to allow efficient automatic alignment. The Ll4Gllens can provide about 15° of accuracy in a simple level sensing circuit, and a....
The battery low-voltage detector uses a CD4093 Schmitt trigger and a capacitor that acts as a 1-bit dynamic RAM. The c..
This circuit uses a TBA820 audio 1C to amplify underwater sounds. The microphone must be waterproofed. This project was originally used in a home aquarium to monitor fish sounds...
A power MOSFET and a quad exclusive-OR oscillator makes an effective solid-state relay. Figure 75-5(a)"s capacitively iso..
Examples of RF and audio ANL circuits. Positive and negative clipping occurs in both circuits. The circuit at A i..
The circuit uses the LTC1043 in a variable gain amplifier which features continuously variable gain, gain stability of 20 ppm/°C, and single-ended or differential inputs. The circuit uses two separate LTC1043s. LTC1043B is continuously clocked by a....
The resulting timer circuit is made from a CD4060, includes an oscillator and a 14 stage binary counter, two CD4040's, which are 12 stage binary counters, a CD4012 Dual Nand gate and a CD4013 Dual D Latch. The CD4060 is connected to a 32768 Hz ECS 3X8....
The circuit operates from a 5-V supply arid has a current consumption of 2 mA. The output is a current source that drives or suppresses a current of more than 75 with a voltage swing of 4.5 V. The Q-killer circuit eliminates distortion of the output pulses....
The sunset lamp comes on at full brightness and then slowly fades out over 1.5 hours time and stays off until power is recycled...
Using only 2 capacitors, 3 resistors, 4 seven-segment Display, 1 xtal, 2 switches n.o. and 1 Microcontroller PIC, you can build this Digital Led Clock. you can use common anode or common cathode display, just select the display type. Here is the pinout....
This preamplifier was designed to cope with CD players, tuners, tape recorders etc., providing a gain of 4, in order to drive less sensitive power amplifiers. As modern Hi-Fi home equipment is frequently fitted with small loudspeaker cabinets, the bass....
An NE567 tone decoder, tuned to the transceiver"s CW offset frequency, ensures that the transceiver will be tran..
By vocalizing the numbers and symbols of its~eypad, the phone provides an audible confirmation that is useful to the blind. The serial-interface, 2 K-byte x 8-bit ROM (!C4) stores programmed sequences of instructions that are executed by the....
The circuit will provide 3 preset currents which will remain constant despite variations of ambient temperature or line voltage. ZDl produces-a temperature stable reference voltage which is applied to the noninverting input of ICl. 100% feedback is applied....
The circuit is powered by the receiver's pack, the current drain is low, specially if compared to drain of servos. U1a VZ2 and Q1 are the CURRENT source of the sensor VZ2 is temperature compensated, use the listed component except for Q1 there you can use....
The dc voltage present on a telephone line is usually around 45 to 50 V on-hook and 6 V off-hook. This circuit uses This drop in voltage to activate a relay. The relay controls a cassette tapeTecorder...
This was my first sucessful project with a PIC chip. I used a 16F84 with a 10MHz resonator with built in caps. Click here to view the source code to this project. The code is written in Hi-Tech C. Click here to download the source code to this project. File....
The circuit draws so little current that the shelf-line of the battery is the limiting factor. The only current drawn is the leakage of the transistor. The circuit is shown in the form of a water level alarm but by using different forms of probe can act as a....
This monitor uses a common 7 41 amp configured as a comparator and a low cost nontransistor as an output driver. With no liquid detected, a voltage of about 2. 92 V is present in the op amp"s inverting input at pin 2. The 100-KO resistors establish a....
Ql and Q2 switch the primary windings of transformer Tl via a square wave at a frequency determined by its magnetic properties. Diodes Dl and D2 provide base return paths for the feedback current of Ql and Q2. The output winding of T1 is connected to a....
This general purpose signal source serves very well in signal-tracing applications. The output level is variable to more than 1 Vrms into a 50 O load. Almost any crystal in the 1 to 15 MHz range can be used. Ql forms a Colpitis oscillator with the output....
This project is designed to program the 8-pin PIC12c508A and 18pin PIC16F84 microcontroller chips to support the projects we have designed, however it will also program a number of other 8-pin & 18-pin microcontrollers and the full list can be seen when....
The circuit uses Ql to buffer the right-channel balance output while Q2 and Q3 form a VOX circuit. When the signal level from the microphone goes high, the output of the VOX also goes high and the multiplexer inside IC1 switches the high-gain left-channel....
The circuit diagram of the Lie Detector is shown above. It consists of three transistors (TR1 to TR3), a capacitor (C1), two lights or LEDs (L1 & L2), five resistors (R1 to R5), and a variable resistor (VR1). This circuit is based on the fact that a....
This circuit does not require an output transformer or an output coupling capacitor; the annunciator can easily be turned on or off by a control input voltage driving a 10Mohm input resistor, R3. For a smaller acoustic output, replace output transistor Ql,....
Relay K1 has a low-impedance coil and K2 has a high-impedance coil. When a sensor opens, current is routed throu..
This is probably one of the most legendary fuzz pedals that has ever existed, and for good reason too! This thing can produce some completely saturated fuzz that is capable of slipping into feedback easily if you crank it up loud enough. I just can't say....
This waveshape generator is basically a slow running oscillator with variable attack and decay. A variable amplitude (high impedance) output is available via the 2M potentiometer. B shows an add-on circuit which should be used if a low impedance output is....
Filtered 15 V de is applied to a series circuit consisting of thermistor R2 and parallel combination of resistors Rl and R3. Transistor Ql acts as a switch whose state is determined by the setting of potentiometer R3, which is first set so just enough....
This circuit provides on/off switching, soft starting, current monitoring, current tripping, and protection against overcurrent for a 30 Vdc power supply at normal load currents up to 2 A. The switch is turned on by an "on" command pulse; it is turned off by....
