New Circuits Page 218
- Page 218
-
This project uses only a few of the instructions that come with PicBasic, but serves to show how easy PicBasic really is. It also shows how PicBasic strongly resembles programming the BASIC Stamp. Here we are using the serin command, and a couple if then....
-
-
To buffer a test generator to the outside world requires an amplifier with sufficient bandwidth and power handling capability. The circuit is a very simple unity gain buffer. It has a fairly high input impedance, a 50 ohm output impedance, a wide bandwidth,....
-
The LT®1462/LT1464 duals and the LT1463/LT1465 quads
are the first micropower op amps to offer picoampere input
bias currents and unity-gain stability when driving capacitive
loads. For each amplifier, the LT1462/LT1463 consume
only 28mA of supply....
-
When the vehicle"s backup lights kick on, or when the manual switch (SI) is closed, a small current is fed to the base of Ql...
-
Each time the switch closes, the voltage on Cl causes inverter A to change state, with positive feedback from inverter B. Resistor Rl delays the charging and discharging of Cl, making the circuit virtually immune to contact bounce. The circuit works....
-
This circuit allows the effective power in a load to be controlled by varying the duty cycle of the on/off ratio of l..
-
-
The Car shows the distance a train travels on a 5 digit LCD display. The distance is indicated down to 1/100th of a mile (about the length of a 50 foot car) with an accuracy of approximately plus 2 percent using a standard 33 inch freight car wheel.....
-
Gates U1a and U1b are configured as a low-frequency oscillator. The output waveform at pin 11 is nonsymmetrical with the positive portion of the signal, making up only 20% of the time period. Diode D1, a 1N914 general-purpose unit, together with C1, R1,....
-
A MOSFET is used as a wideband buffer amplifier. T1 is wound on a toroid of approximately /f diameter, with material suitable for frequency (usually 1- to 20-MHz range). The turns ratio should be about 4:1 depending on load impedance. Typically, at 4 MHz,....
-
This high-performance video-camera link transmits signals from your video camera to your VCR, or from your VCR to TVs throughout your home. The first stage of the rf chain is a crystal-controlled oscillator, Q1, with a frequency of 60 to 65 MHz, which is....
-
This amplifier does not claim to be "state of the art", and in fact the base design is now over 20 years old. It is a simple amp to build, uses commonly available parts and is stable and reliable. The design featured is a slight modification of an amp I....
-
-
The LR inputs are summed, dated and drive a comparator. The comparator senses level and generates a transition when audio inputs go above or below preset thresholds. The number of these transitions (corresponding to rapid volume changes) are integrated and....
-
The tester gives an audible indication, making it unnecessary for the user to look directly at the instrument to observe a meter reading. In addition, the current and voltage of the tester are strictly limited. It can apply no more than 0.6 volts dc and no....
-
The unit consists of a sensor, timer, and electric water pump. The sensor is embedded in the soil, and when dry, the electronics operate the water pump for a preset time. The circuit is composed of a level sensitive Schmitt trigger, variable time monostable,....
-
Running a bath can end in a minor domestic disaster if you forget to turn off the taps in time. This indicator activ..
-
If you face the challenge of adding a second, independently controlled light source to an existing ceiling lamp controlled by a wall switch, you may find that stringing a second power line is impossible. First, you can replace the wall switch by the circuit....
-
You can drop all off the transistors and resistors if your motors don`t drain too much current. You only need a 74F139 or 74S139 NOT the LS version. The chip can provide peak currents up to 100mA for a short time (<1 second) and to one output at a time.....
-
This circuit, connected to 32 Ohm impedance mini-earphones, can detect very remote sounds. Useful for theatre, cinema and lecture goers: every word will be clearly heard. You can also listen to your television set at a very low volume, avoiding to bother....
-
The circuit in Figure 1 is a dual, grounded-lamp backlight
inverter that operates from an input of 9V to 24V, delivers
current from 0mA to 9mA per CCFL and has a dimming
ratio greater than 100:1. The LT1768 in the circuit is a
350kHz fixed frequency,....
-
Everytime the push-to-talk button is closed the light will go on. The antenna samples the output RF from the transmitter. That signal is then rectified (detected) by germanium diode Dl, and used to charge capacitor C2. The dc output is used to trigger a....
-
Circuit Magic is an electrical circuits simulation program specifically designed for students teaching basics electronics, electrical laws & circuit theory. Unlike many electronic circuit analyzers, Circuit Magic can analyze circuits like a man. Circuits....
-
Many applications, such as computers, require signals for initializing conditions during start-up. Other applications such as test equipment require activation of test signals in sequence. SE555/NE555 circuits may be connected to provide such sequential....
-
This project and your efforts will provide you with a 0.55...3 watt input to easily 10 watt output. The two linear amplifiers are ment for use with QRP SSB/CW/FM/AM transmitters on the amateur bands 15 and 17 meters can be powered from a 12 volt DC supply.....
-
In this application, the Vl-7660 is connected as a voltage splitter. Note that the normal output pin is connected to ground and the normal ground pin is used as the output. The switches that allow the charge pumping are bidirectional; therefore, charge....
-
You can use an ADT7461 single-channel temperature monitor; an ADG708 low-voltage, low-leakage CMOS 8-to-1 multiplexer; and three standard 2N3906 pnp transistors to measure the temperature of three separate remote thermal zones (Figure 1). Multiplexers have....
-
This circuit shows the TP5700 directly interfacing to a low-voltage DTMF generator. VREGt supplies the necessary 2-V minimum bias to enable the TP5380 to sense key closures and pull its mute output high. VREGt then switches to a 3-V regulated output to....
-
This circuit generates simultaneously, a triangle and a square waveform. It is self starting and has no latch up problems. IC1 is an integrator with a slew rate determined by CT and RT and IC2 is a Schmitt trigger. The output of IC1 ramps up and down between....
-
Frequency accuracy has been a topic of special interest to many amateurs and experimenters since the early days of radio. Until recently, the best frequency standard available to most hams was a crystal oscillator carefully adjusted to zero-beat with a....
-
The op amp is wired as a 2 noninverting dc amplifier with a gain that is determined by the R3/R2 ratio. The inp..
-
This circuit accepts bipolar control inputs of ± 5 V and provides a phase-chopped output to a dc load (such as a servo motor) of the same polarity as the input. The rms voltage of the output is closely proportional to the control input voltage. N-channel....
-
This matrix can show the values of two variables, for example, frequency and voltage. The display is a graph made from a matrix of LEDs. The LEDs on each axis are color coded, red for out of tolerance and green for in, fanning a red band around the inner....
-
No Description available...
-
The DC output at Pin 1 vanes linearly with the RMS input at Pin 4. 2 CT is tweaked until the svnc signal is in phase with the AC signal. An ac voltmeter may be easily constructed. Simplicity of the circuit and low component count make it particularly....
-
Figure 9 is a detailed schematic of Figure 8s concept. The
resonance loop is comprised of Q4 and the CMOS inverter
based oscillator. The amplitude loop centers around the
LT1375 switching regulator. Figure 10 shows waveforms.
Traces A and B are Q2 and Q1....
-
This unit picks up your ATV signal by sampling the transmission line with negligible insertion loss. It uses 2 N connectors for input and output connections. A BNC connector is used on the video output. The detected output is connected to your monitor and....
-
An oscillator/amplifier is resistively tunable over a wide frequency range. Feedback circuits containing operational amplifiers, resistors, and capacitors synthesize the electrical effects of an inductance and capacitance in parallel between the input....
-
The circuit shown below is a basic latching circuit consisting of a quad 2-input NAND Gate IC. It is configured such that the flip flop circuit U1A and U1B has both its input held at logic "1". Pin 1 is held at logic "1" by the magnetic contact and pin 6 is....
-
his coil is home-made. It is actually a single layer 'tapped' air core coil. Please refer to my special section on how to make the DRAIN Coil. Once it is made, the tapped leg goes into the middle hole (Refer to CHART I), but make sure you have the coil....
-
Maxim's MAX038 function generator chip is capable of producing nearly constant amplitude sine, square, and triangle waves with a low output impedance, from a very low frequency to more than 20 MHz. Basically, a function generator on a chip. Here is a....
-
A humidity sensor with temperature compensation built-in. Never apply a DC voltage to the sensor, even measuring the sensor with an ohmmeter will damage the device, always ensure that an AC voltage is applied. Avoid condensation, freezing, dust, mist, oil,....
-
A high voltage step-up DC power supply using adjustable flyback conversion...
-
Works on AVR controllers with RAM and a hardware UART. This code is easily modified to integrate with ROM applications to provide the ability to monitor and interact with ROM applications via an terminal simulation program over an RS-232 port. It can also be....
-
Isolated flyback converters usually evoke thoughts-or bitter memories-of custom transformers, slipped delivery schedules, and agency-approval problems. Off-the-shelf flyback transformers carry isolation ratings of only 300 to 500V and rarely of as much as 1....
-
A diode (IN4148) is used as a temperature sensor. IC2 is an A/D converter with BCD output. A refere..
-
In his circuit Marin has used two transistors wired as a high gain compound pair. Transistor T1 may be a 2N2222A and T2 a BC108. The current gain will be the product of each transistors beta, which will be a minimum of 140 x 110 or 15400. The power supply....
-
This simple circuit allows you to record any IR remote control signal on your PC, and then play it back. This is particularly useful if you want to control appliances such as TVs, VCRs, CDs etc. from your computer. The device simply connects to the parallel....
-
The Sun - Up Alarm can be used to provide a audible alarm for when the sun comes up or it can be used in a dark area and detect when a light comes on. It can also be used to detect a light beam, headlights etc. The circuit works as follows. The....
-
It consists of a 4047 low-power monostable/astable multivibrator, IC1, used in the astable mode to provide the timing pulses to control the flash rate of the LEDs. To accomplish the astable mode, pins 4, 5, 6, and 14 are connected to +12VDC and pins 7, 8,....
-
When this circuit is turned on, the natural offset of the devices serves as an automatic starting voltage. Assume that ..
-
This project is based on a probe logic states, capable of measuring levels from TTL (5v) to state levels of PLC's (24v). For this we have employed the use of the PIC 12F683 microcontroller, which by its nature is capable of operating at low voltages, in this....
-
The NE555 circuit is a basic one-shot timer with a relay connected between the output and ground. It is triggered with the normally open momentary contact switch, which when operated, grounds the trigger input at pin 2. This causes a high output to....
-
When measure video signal with oscilloscope, video line selector is very useful to find a scan line. The line selecter generates trigger pulse at selected line, oscilloscope will display only selected line. This is a very simple video line selector...
-
Most of us don`t have the luxury of building a 1/4, 1/2 or even a 5/8 wavelength vertical antenna for HF. We have to settle for something a little shorter. (A lot shorter, in the case of people following the FCC`s Part 15 rules, which limit them to 3 meters....
-
A large area photodiode and current to frequency converter combined in a clear plastic 8-pin DIL package. The output is a pulse train whose frequency is directly proportional to the light intensity. The output is CMOS compatible (use a 3k3 pulldown resistor....
-
This circuit combines a current source and a platinum RTD bridge to form a complete high-accuracy thermometer. Th..
-
Here`s how you can make an electronic speed controler (ESC) for your remote control car, boat or even an airplane using an old servo and some MOSFETS. Please note that this ESC has a very limited control range. Meanining that it will act almost like but....
-
That circuit is based on a 14-pin DIL IC capable of producing sine, square, triangular, sawtooth and pulse waveforms of high accuracy and stability. The frequency may be selected to be from 0.001Hz to 1Mhz, Frequency modulation and sweeping can be....
-
After the 2-way active loudspeaker circuit, give a complete electronic section circuit of one 3-way active loudspeaker. The speaker?s choice will become from you, because the particular circuit has the driving possibility all almost trade loudspeakers. The....
-
To amplify small current signals such as from ah electron-collector inside a vacuum chamber, it is convenient for reasons of noise and bandwidth to have a "head-amplifier" attached to the chamber. The op amp N1 is a precision bipolar device with extremely....
-
In many oscilloscopes, the most sensitive range is 2 to 5 mV, although it is often possible to improve this to 1 to 2 m..
-
A Motorola TCA5500 or TCA5550 can provide a stereo preamplifier system with tone controls. This circuit provides a gain of about 10X, a 14-dB tone-control range, a 75-dB volume control range, and it can operate from 8 to 18 Vdc. IC2 provides 15 V for ICl,....
-
A 'TV modulator' is really no more than a transmitter. It is a very small transmitter, admittedly, but none the less that is what it is. What does a modulator actually do? In general -and this design is no exception to the rule - it is a simple oscillator....
-
In this project, you will make a simple low-power broadcast-type circuit, using a crystal oscillator integrated circuit and an a collector modulated AM oscillator. You can connect the circuit to the an electrec microphone (pointed out in gray on the diagram)....
-
The RF signal is passed from the antenna through CI to the tuned circuit made up of LI and C2. One end of L2 feeds th..
-
This article describes a 2-Input alarm developed on the PIC LICK-1 Module using a Microchip PIC16F628-04. The program uses the internal 4MHz oscillator and if any other frequency is used, the timer values will need to be changed. A two zone alarm means the....
-
The original version of P05 has been around for a very long time now (around 4 years), and there are some worthwhile reasons for the updates. Although the performance of the original was not lacking in any way, I decided to change to adjustable regulators.....
-
This circuit is a small +5V power supply, which is useful when experimenting with digital electronics. Small inexpensive wall tranformers with variable output voltage are available from any electronics shop and supermarket. Those transformers are easily....
-
The tool is based on a NE555 (or LM555) timer i.c., wired as an astable multivibrator. The frequency of the multivibrator is determined by the value of the unknown capacitor Cx. The circuit can be fed by a small battery. I use myself a 9 V block battery....
-
This circuit reads and stores voltages, tbus freezing the meter reading even after tbe probes are removed. The op amp is configured as a unitygain voltage follower, witb C1 situated at tbe input to store tbe voltage. For better performance, use an....
-
48 LEDs total, 24 on each side of the board. This gives higher resolution patterns, and they can be seen from both sides of the bike. The LEDs are controlled from a series of 74x373 ICs connected to an 8 bit bus on the microcontroller. As opposed to shift....
-
This is an improved IR remote control extender circuit. It has high noise immunity, is resistant to ambient and reflected light and has an increased range from remote control to the extender circuit of about 7 meters. It should work with any domestic....
-
The circuit will provide both a sine-and square-wave output for frequencies from below 20 Hz to above 20 kHz. The frequency of oscillation is easily tuned by varying a single resistor. This is a considerable advantage over Wien-Bridge circuits where two....
-
Two MC1408—8-bit D/A converters, A and in the circuit diagram, are used. The four least-significant bits of A are tied to zero. The four most significant bits of the 12-bit data are connected to the remaining four input pins. The eight least significant....
-
A 2N3904 in the base circuit sets the `Q' point of the amplifier. FM subcarrier audio at 4.5 MHz is also injected at this point through a 3300 ohm resistor and a DC blocking capacitor. A high frequency 5-watt RF power transistor (2SC1909) serves as the last....
-
This project describes how to build a "soft touch" switch. By "soft touch" we mean that you have to push once to set device ON and push again to set device OFF. This kind of switch works by latching a relay to ON state with push of a button and with another....
-
A CMOS oscillator (U1A) drives. U1B through U1F, which drives Ql, which generates a 12-Vpp square wave across the primary ..
-
The unit is simple to build, and does not need really low noise opamps, since they only act as a modulator oscillator. I used 1458 dual types in the prototype, and they are more than good enough. The transistors can be any low noise NPN type, and they are....
-
In this circuit, Ql is a simple amplifier that has its gain controlled by a variable emitter resistance supplied by FET Q2. In ..
-
The circuit shown will switch on and off a resistive or inductive load up to 800VA with the possibility to adjust both the on and off period. Switching takes place during the zero crossing of the sine wave. The switch on point is around the zero crossing but....
-
The oscillator output of the XR-567 can be amplified using the output amplifier and high-current logic output available at pin 8. In this manner, the circuit can switch 100-mA load currents without sacrificing oscillator stability. ..
-
The circuit on the right uses three bipolar transistors to accomplish the same result with the touch contact referenced to the negative or ground end of the supply. Since the base of a bipolar transistor draws current and the current gain is usually less....
-
When an inverter is biased with one resistor from its input to output in the range of 100 KOhmhm to 10 and is capacitor c..
-
This simple circuit mixes two or more channels into one channel (eg. stereo into mono). The circuit can mix as many or as few channels as you like and consumes very little power. The mixer is shown with two inputs, but you can add as many as you want by just....
-
Among the signals below 550 kHz are maritime mobile, distress, radio beacons, aircraft weather, European Longwave-AM broadcast, and point-to-point communications. The low-frequency converter converts the 10 to 500kHz LW range to a 1010 to 1550kHz MW range,....
-
The 7915 (at least the "made in Morocco" I used) needs a small load (some mA) to work correctly. If you get funny voltages (-18.4V or so), put a resistor from the 7915 output to ground (2k2 works good). Or it might be a good idea to put the "power on" LED....
-
It uses old pulse dial handsets and replaces the AC bell set with a 9 volt DC buzzer. The whole circuit runs from a 12 volt regulated DC supply and is suitable for short term battery operation (eg: Gel Cell). The Link is designed to enable one call at a time....
-
When power is first applied, three things happen: light -driving transistor Ql is switched on due to a iow output from U2 pin 3; timer U1 begins its timing cycle, with the output, pin 3, becoming high, inhibiting U2"s trigger, pin 2, via D2; and charge....
-
This is a very simple circuit to build, just take note of the control pins on each IC, since both have enable inputs for counting or output, but once set you don't need to worry about them. From left to right, the first IC is a binary counter, 74ls163, that....
-
Having to use the infrared remote control, we will procure in addition to modulate the Nutchip infrerossi receiver. Do not let the name fool you, because more than one module component that looks like a large transistor. We use as a reset Nutchip external RC....
-
Despite the popularity of digital devices, real world signals are typically represented by analog signals. Digital control systems process real world analog signals by using an analog-to-digital converter (ADC) to convert analog signals to digital.....
-
Figure 1 shows how to digitally program the on-time of a one-shot multivibrator circuit. More and more, the Internet is playing a role in control operations in industrial and R&D endeavors and in household appliances. One-shot circuits are popular....
-
The circuit described here is for a general purpose device that can control DC devices which draw up to a few amps of current. The circuit may be used in either 12 or 24 Volt systems with only a few minor wiring changes. This device has been used to control....
-
Speed control is accomplished by pulse width modulating the gates of two MGP20N45 TMOS devices. Therefore, motor speed is proportional to the pulse width of the incoming digital signal, which can be generated by a microprocessor or digital logic. The....
-
TTL inverter 74LS14 has an internal 16-Kohm, pull-up resistor that pulls the gate input high when the switch is open. As you close the switch, the 4.7uF capacitor discharges on the first contact. If the switch contacts bounce open, the internal resistor....
-
This circuit is used to meter the audio power output of an amplifier feeding a speaker. RY1 is actuated if excess ..
-
This device is a microprocessor controlled waveform generator that can be used for driving a voltage controlled stereo panner for music applications. Panning is simply the movement of a mono audio signal between the left and right channels of a stereo sound....
-
The ROMs or PROMs must have the correct code for converting the data from the NE5037 -used as address for the ROMs or PROMs-to the appropriate segment driver codes. The displayed amount could easily be converted to degrees Fahrenheit, °F, by the....
-
This unit uses one TSAL6100 IR/LED emitter from Digi-Key. This IR diode has a narrow (10 degree) radiation pattern at 940 NM. It is driven via 2n2904 transistor for maximum current pulses. The detector is a Vishay TSOP4838 38Khz integrated receiver module.....
-
This circuit converts surrounding radio frequency waves to electric power. It can provide 40 Volts at 10 Watts indefinitely. The output power can be improved playing with the antenna. Placing the antenna near large metal objects gives more power. Antenna....
-
A loop antenna can greatly improve medium wave reception. Loop antennas
are directional and receive signals along the plane of the windings. The
directional quality improves signal to noise ratio of the desired signal
while rejecting signals perpendular....
This project uses only a few of the instructions that come with PicBasic, but serves to show how easy PicBasic really is. It also shows how PicBasic strongly resembles programming the BASIC Stamp. Here we are using the serin command, and a couple if then....
To buffer a test generator to the outside world requires an amplifier with sufficient bandwidth and power handling capability. The circuit is a very simple unity gain buffer. It has a fairly high input impedance, a 50 ohm output impedance, a wide bandwidth,....
The LT®1462/LT1464 duals and the LT1463/LT1465 quads are the first micropower op amps to offer picoampere input bias currents and unity-gain stability when driving capacitive loads. For each amplifier, the LT1462/LT1463 consume only 28mA of supply....
When the vehicle"s backup lights kick on, or when the manual switch (SI) is closed, a small current is fed to the base of Ql...
Each time the switch closes, the voltage on Cl causes inverter A to change state, with positive feedback from inverter B. Resistor Rl delays the charging and discharging of Cl, making the circuit virtually immune to contact bounce. The circuit works....
This circuit allows the effective power in a load to be controlled by varying the duty cycle of the on/off ratio of l..
The Car shows the distance a train travels on a 5 digit LCD display. The distance is indicated down to 1/100th of a mile (about the length of a 50 foot car) with an accuracy of approximately plus 2 percent using a standard 33 inch freight car wheel.....
Gates U1a and U1b are configured as a low-frequency oscillator. The output waveform at pin 11 is nonsymmetrical with the positive portion of the signal, making up only 20% of the time period. Diode D1, a 1N914 general-purpose unit, together with C1, R1,....
A MOSFET is used as a wideband buffer amplifier. T1 is wound on a toroid of approximately /f diameter, with material suitable for frequency (usually 1- to 20-MHz range). The turns ratio should be about 4:1 depending on load impedance. Typically, at 4 MHz,....
This high-performance video-camera link transmits signals from your video camera to your VCR, or from your VCR to TVs throughout your home. The first stage of the rf chain is a crystal-controlled oscillator, Q1, with a frequency of 60 to 65 MHz, which is....
This amplifier does not claim to be "state of the art", and in fact the base design is now over 20 years old. It is a simple amp to build, uses commonly available parts and is stable and reliable. The design featured is a slight modification of an amp I....
The LR inputs are summed, dated and drive a comparator. The comparator senses level and generates a transition when audio inputs go above or below preset thresholds. The number of these transitions (corresponding to rapid volume changes) are integrated and....
The tester gives an audible indication, making it unnecessary for the user to look directly at the instrument to observe a meter reading. In addition, the current and voltage of the tester are strictly limited. It can apply no more than 0.6 volts dc and no....
The unit consists of a sensor, timer, and electric water pump. The sensor is embedded in the soil, and when dry, the electronics operate the water pump for a preset time. The circuit is composed of a level sensitive Schmitt trigger, variable time monostable,....
Running a bath can end in a minor domestic disaster if you forget to turn off the taps in time. This indicator activ..
You can drop all off the transistors and resistors if your motors don`t drain too much current. You only need a 74F139 or 74S139 NOT the LS version. The chip can provide peak currents up to 100mA for a short time (<1 second) and to one output at a time.....
This circuit, connected to 32 Ohm impedance mini-earphones, can detect very remote sounds. Useful for theatre, cinema and lecture goers: every word will be clearly heard. You can also listen to your television set at a very low volume, avoiding to bother....
Everytime the push-to-talk button is closed the light will go on. The antenna samples the output RF from the transmitter. That signal is then rectified (detected) by germanium diode Dl, and used to charge capacitor C2. The dc output is used to trigger a....
Circuit Magic is an electrical circuits simulation program specifically designed for students teaching basics electronics, electrical laws & circuit theory. Unlike many electronic circuit analyzers, Circuit Magic can analyze circuits like a man. Circuits....
Many applications, such as computers, require signals for initializing conditions during start-up. Other applications such as test equipment require activation of test signals in sequence. SE555/NE555 circuits may be connected to provide such sequential....
This project and your efforts will provide you with a 0.55...3 watt input to easily 10 watt output. The two linear amplifiers are ment for use with QRP SSB/CW/FM/AM transmitters on the amateur bands 15 and 17 meters can be powered from a 12 volt DC supply.....
In this application, the Vl-7660 is connected as a voltage splitter. Note that the normal output pin is connected to ground and the normal ground pin is used as the output. The switches that allow the charge pumping are bidirectional; therefore, charge....
This circuit shows the TP5700 directly interfacing to a low-voltage DTMF generator. VREGt supplies the necessary 2-V minimum bias to enable the TP5380 to sense key closures and pull its mute output high. VREGt then switches to a 3-V regulated output to....
This circuit generates simultaneously, a triangle and a square waveform. It is self starting and has no latch up problems. IC1 is an integrator with a slew rate determined by CT and RT and IC2 is a Schmitt trigger. The output of IC1 ramps up and down between....
The op amp is wired as a 2 noninverting dc amplifier with a gain that is determined by the R3/R2 ratio. The inp..
This circuit accepts bipolar control inputs of ± 5 V and provides a phase-chopped output to a dc load (such as a servo motor) of the same polarity as the input. The rms voltage of the output is closely proportional to the control input voltage. N-channel....
This matrix can show the values of two variables, for example, frequency and voltage. The display is a graph made from a matrix of LEDs. The LEDs on each axis are color coded, red for out of tolerance and green for in, fanning a red band around the inner....
The DC output at Pin 1 vanes linearly with the RMS input at Pin 4. 2 CT is tweaked until the svnc signal is in phase with the AC signal. An ac voltmeter may be easily constructed. Simplicity of the circuit and low component count make it particularly....
This unit picks up your ATV signal by sampling the transmission line with negligible insertion loss. It uses 2 N connectors for input and output connections. A BNC connector is used on the video output. The detected output is connected to your monitor and....
An oscillator/amplifier is resistively tunable over a wide frequency range. Feedback circuits containing operational amplifiers, resistors, and capacitors synthesize the electrical effects of an inductance and capacitance in parallel between the input....
The circuit shown below is a basic latching circuit consisting of a quad 2-input NAND Gate IC. It is configured such that the flip flop circuit U1A and U1B has both its input held at logic "1". Pin 1 is held at logic "1" by the magnetic contact and pin 6 is....
his coil is home-made. It is actually a single layer 'tapped' air core coil. Please refer to my special section on how to make the DRAIN Coil. Once it is made, the tapped leg goes into the middle hole (Refer to CHART I), but make sure you have the coil....
Maxim's MAX038 function generator chip is capable of producing nearly constant amplitude sine, square, and triangle waves with a low output impedance, from a very low frequency to more than 20 MHz. Basically, a function generator on a chip. Here is a....
A humidity sensor with temperature compensation built-in. Never apply a DC voltage to the sensor, even measuring the sensor with an ohmmeter will damage the device, always ensure that an AC voltage is applied. Avoid condensation, freezing, dust, mist, oil,....
A high voltage step-up DC power supply using adjustable flyback conversion...
Works on AVR controllers with RAM and a hardware UART. This code is easily modified to integrate with ROM applications to provide the ability to monitor and interact with ROM applications via an terminal simulation program over an RS-232 port. It can also be....
A diode (IN4148) is used as a temperature sensor. IC2 is an A/D converter with BCD output. A refere..
In his circuit Marin has used two transistors wired as a high gain compound pair. Transistor T1 may be a 2N2222A and T2 a BC108. The current gain will be the product of each transistors beta, which will be a minimum of 140 x 110 or 15400. The power supply....
This simple circuit allows you to record any IR remote control signal on your PC, and then play it back. This is particularly useful if you want to control appliances such as TVs, VCRs, CDs etc. from your computer. The device simply connects to the parallel....
The Sun - Up Alarm can be used to provide a audible alarm for when the sun comes up or it can be used in a dark area and detect when a light comes on. It can also be used to detect a light beam, headlights etc. The circuit works as follows. The....
It consists of a 4047 low-power monostable/astable multivibrator, IC1, used in the astable mode to provide the timing pulses to control the flash rate of the LEDs. To accomplish the astable mode, pins 4, 5, 6, and 14 are connected to +12VDC and pins 7, 8,....
When this circuit is turned on, the natural offset of the devices serves as an automatic starting voltage. Assume that ..
This project is based on a probe logic states, capable of measuring levels from TTL (5v) to state levels of PLC's (24v). For this we have employed the use of the PIC 12F683 microcontroller, which by its nature is capable of operating at low voltages, in this....
The NE555 circuit is a basic one-shot timer with a relay connected between the output and ground. It is triggered with the normally open momentary contact switch, which when operated, grounds the trigger input at pin 2. This causes a high output to....
When measure video signal with oscilloscope, video line selector is very useful to find a scan line. The line selecter generates trigger pulse at selected line, oscilloscope will display only selected line. This is a very simple video line selector...
Most of us don`t have the luxury of building a 1/4, 1/2 or even a 5/8 wavelength vertical antenna for HF. We have to settle for something a little shorter. (A lot shorter, in the case of people following the FCC`s Part 15 rules, which limit them to 3 meters....
A large area photodiode and current to frequency converter combined in a clear plastic 8-pin DIL package. The output is a pulse train whose frequency is directly proportional to the light intensity. The output is CMOS compatible (use a 3k3 pulldown resistor....
This circuit combines a current source and a platinum RTD bridge to form a complete high-accuracy thermometer. Th..
Here`s how you can make an electronic speed controler (ESC) for your remote control car, boat or even an airplane using an old servo and some MOSFETS. Please note that this ESC has a very limited control range. Meanining that it will act almost like but....
That circuit is based on a 14-pin DIL IC capable of producing sine, square, triangular, sawtooth and pulse waveforms of high accuracy and stability. The frequency may be selected to be from 0.001Hz to 1Mhz, Frequency modulation and sweeping can be....
After the 2-way active loudspeaker circuit, give a complete electronic section circuit of one 3-way active loudspeaker. The speaker?s choice will become from you, because the particular circuit has the driving possibility all almost trade loudspeakers. The....
To amplify small current signals such as from ah electron-collector inside a vacuum chamber, it is convenient for reasons of noise and bandwidth to have a "head-amplifier" attached to the chamber. The op amp N1 is a precision bipolar device with extremely....
In many oscilloscopes, the most sensitive range is 2 to 5 mV, although it is often possible to improve this to 1 to 2 m..
A Motorola TCA5500 or TCA5550 can provide a stereo preamplifier system with tone controls. This circuit provides a gain of about 10X, a 14-dB tone-control range, a 75-dB volume control range, and it can operate from 8 to 18 Vdc. IC2 provides 15 V for ICl,....
A 'TV modulator' is really no more than a transmitter. It is a very small transmitter, admittedly, but none the less that is what it is. What does a modulator actually do? In general -and this design is no exception to the rule - it is a simple oscillator....
In this project, you will make a simple low-power broadcast-type circuit, using a crystal oscillator integrated circuit and an a collector modulated AM oscillator. You can connect the circuit to the an electrec microphone (pointed out in gray on the diagram)....
The RF signal is passed from the antenna through CI to the tuned circuit made up of LI and C2. One end of L2 feeds th..
This article describes a 2-Input alarm developed on the PIC LICK-1 Module using a Microchip PIC16F628-04. The program uses the internal 4MHz oscillator and if any other frequency is used, the timer values will need to be changed. A two zone alarm means the....
The original version of P05 has been around for a very long time now (around 4 years), and there are some worthwhile reasons for the updates. Although the performance of the original was not lacking in any way, I decided to change to adjustable regulators.....
This circuit is a small +5V power supply, which is useful when experimenting with digital electronics. Small inexpensive wall tranformers with variable output voltage are available from any electronics shop and supermarket. Those transformers are easily....
The tool is based on a NE555 (or LM555) timer i.c., wired as an astable multivibrator. The frequency of the multivibrator is determined by the value of the unknown capacitor Cx. The circuit can be fed by a small battery. I use myself a 9 V block battery....
This circuit reads and stores voltages, tbus freezing the meter reading even after tbe probes are removed. The op amp is configured as a unitygain voltage follower, witb C1 situated at tbe input to store tbe voltage. For better performance, use an....
This is an improved IR remote control extender circuit. It has high noise immunity, is resistant to ambient and reflected light and has an increased range from remote control to the extender circuit of about 7 meters. It should work with any domestic....
The circuit will provide both a sine-and square-wave output for frequencies from below 20 Hz to above 20 kHz. The frequency of oscillation is easily tuned by varying a single resistor. This is a considerable advantage over Wien-Bridge circuits where two....
Two MC1408—8-bit D/A converters, A and in the circuit diagram, are used. The four least-significant bits of A are tied to zero. The four most significant bits of the 12-bit data are connected to the remaining four input pins. The eight least significant....
A 2N3904 in the base circuit sets the `Q' point of the amplifier. FM subcarrier audio at 4.5 MHz is also injected at this point through a 3300 ohm resistor and a DC blocking capacitor. A high frequency 5-watt RF power transistor (2SC1909) serves as the last....
This project describes how to build a "soft touch" switch. By "soft touch" we mean that you have to push once to set device ON and push again to set device OFF. This kind of switch works by latching a relay to ON state with push of a button and with another....
A CMOS oscillator (U1A) drives. U1B through U1F, which drives Ql, which generates a 12-Vpp square wave across the primary ..
The unit is simple to build, and does not need really low noise opamps, since they only act as a modulator oscillator. I used 1458 dual types in the prototype, and they are more than good enough. The transistors can be any low noise NPN type, and they are....
In this circuit, Ql is a simple amplifier that has its gain controlled by a variable emitter resistance supplied by FET Q2. In ..
The circuit shown will switch on and off a resistive or inductive load up to 800VA with the possibility to adjust both the on and off period. Switching takes place during the zero crossing of the sine wave. The switch on point is around the zero crossing but....
The oscillator output of the XR-567 can be amplified using the output amplifier and high-current logic output available at pin 8. In this manner, the circuit can switch 100-mA load currents without sacrificing oscillator stability. ..
The circuit on the right uses three bipolar transistors to accomplish the same result with the touch contact referenced to the negative or ground end of the supply. Since the base of a bipolar transistor draws current and the current gain is usually less....
When an inverter is biased with one resistor from its input to output in the range of 100 KOhmhm to 10 and is capacitor c..
This simple circuit mixes two or more channels into one channel (eg. stereo into mono). The circuit can mix as many or as few channels as you like and consumes very little power. The mixer is shown with two inputs, but you can add as many as you want by just....
Among the signals below 550 kHz are maritime mobile, distress, radio beacons, aircraft weather, European Longwave-AM broadcast, and point-to-point communications. The low-frequency converter converts the 10 to 500kHz LW range to a 1010 to 1550kHz MW range,....
The 7915 (at least the "made in Morocco" I used) needs a small load (some mA) to work correctly. If you get funny voltages (-18.4V or so), put a resistor from the 7915 output to ground (2k2 works good). Or it might be a good idea to put the "power on" LED....
It uses old pulse dial handsets and replaces the AC bell set with a 9 volt DC buzzer. The whole circuit runs from a 12 volt regulated DC supply and is suitable for short term battery operation (eg: Gel Cell). The Link is designed to enable one call at a time....
When power is first applied, three things happen: light -driving transistor Ql is switched on due to a iow output from U2 pin 3; timer U1 begins its timing cycle, with the output, pin 3, becoming high, inhibiting U2"s trigger, pin 2, via D2; and charge....
This is a very simple circuit to build, just take note of the control pins on each IC, since both have enable inputs for counting or output, but once set you don't need to worry about them. From left to right, the first IC is a binary counter, 74ls163, that....
Having to use the infrared remote control, we will procure in addition to modulate the Nutchip infrerossi receiver. Do not let the name fool you, because more than one module component that looks like a large transistor. We use as a reset Nutchip external RC....
The circuit described here is for a general purpose device that can control DC devices which draw up to a few amps of current. The circuit may be used in either 12 or 24 Volt systems with only a few minor wiring changes. This device has been used to control....
Speed control is accomplished by pulse width modulating the gates of two MGP20N45 TMOS devices. Therefore, motor speed is proportional to the pulse width of the incoming digital signal, which can be generated by a microprocessor or digital logic. The....
TTL inverter 74LS14 has an internal 16-Kohm, pull-up resistor that pulls the gate input high when the switch is open. As you close the switch, the 4.7uF capacitor discharges on the first contact. If the switch contacts bounce open, the internal resistor....
This circuit is used to meter the audio power output of an amplifier feeding a speaker. RY1 is actuated if excess ..
This device is a microprocessor controlled waveform generator that can be used for driving a voltage controlled stereo panner for music applications. Panning is simply the movement of a mono audio signal between the left and right channels of a stereo sound....
The ROMs or PROMs must have the correct code for converting the data from the NE5037 -used as address for the ROMs or PROMs-to the appropriate segment driver codes. The displayed amount could easily be converted to degrees Fahrenheit, °F, by the....
This unit uses one TSAL6100 IR/LED emitter from Digi-Key. This IR diode has a narrow (10 degree) radiation pattern at 940 NM. It is driven via 2n2904 transistor for maximum current pulses. The detector is a Vishay TSOP4838 38Khz integrated receiver module.....
This circuit converts surrounding radio frequency waves to electric power. It can provide 40 Volts at 10 Watts indefinitely. The output power can be improved playing with the antenna. Placing the antenna near large metal objects gives more power. Antenna....
A loop antenna can greatly improve medium wave reception. Loop antennas are directional and receive signals along the plane of the windings. The directional quality improves signal to noise ratio of the desired signal while rejecting signals perpendular....
