Top Circuits Page 118
- Page 118
-
This circuit was designed to allow a laptop computer to be powered from a solar power setup. The computer requires 12V at 3. 3A. The circuit is a linear regulator with Mosfet Q4 as the series pass device. A 100kO resistor provides Q4 with a positive....
-
-
-
This is a circuit for an intercom is a is a stand-alone electronic communications system intended for limited or private dialogue. Below schematic shows the application circuit of LM390 on intercom. Gain control can be done by capacitively coupling a....
-
The TV transmitter given here uses UK standard 1 FM modulation for sound and PAL for video modulation. The audio signal to be modulated is pre-amplified using the transistor Q1 and associated components. The transistor Q2 has two jobs: production of carrier....
-
In this project, 8 LEDs are connected to PORT B of a PIC microcontroller. Also a push-button switch is connected to bit 0 of PORT A using a pull-up resistor. When the switch is pressed the LEDs scroll to the right. The circuit diagram of the project is shown....
-
Mobile robots are used in many industrial, commercial, research, and hobby applications. This project is about the control of a mobile robot using servomotors. The robot used in this project is the base of a popular mobile robot known as Boe Bot, developed....
-
-
-
Some ten days ago I installed an all-linear automatic night light circuit to control the lights inside the living room. Circuit consists of three op amps-two used as voltage followers and a third as a comparator. As the schematic shows, all user adjustable....
-
While discussing an all-linear automatic night light circuit I mentioned that I was testing an MCU-based ANLC. Well, I`ve been tweaking the firmware since. The other day I installed the sensor outdoors and have connected the circuit to control 220VAC loads.....
-
The Pierce oscillator is a very simple circuit and as with the ring oscillator also uses inverters (actually just one inverter will do). The principle of operation, however, is very different. While the ring oscillator exploits the incremental propagation....
-
-
-
LEDs are used more and more in motor vehicles, replacing the standard incandescent lamps because they are more energy efficient and have a much longer life expectancy. In this article we describe a simple LED tail light that has been specifically designed....
-
This infrared alarm barrier can be used to detect persons passing through doorways, corridors and small gates. The transmitter emits a beam of infrared light which is invisible to the human eye. The buzzer at the output of the receiver is activated when the....
-
My vintage (62 year old) pole light has always been controlled by a timer ”a source of continual frustration due the requirement of readjustment for the ever-changing seasons. However, after knocking it over (I backed my car into it ), I decided it was time....
-
This circuit delivers an initial voltage of 2. 5V per cell to rapidly charge a car battery. The charging current decreases as the battery charges and when the current drops to 180 mA the charging circuit reduces the output voltage to 2. 35 V per cell,....
-
Here is a solar charger circuit that is used to charge Lead Acid or Ni-Cd batteries using the solar energy power. The circuit harvests solar energy to charge a 6 volt 4. 5 Ah rechargeable battery for various applications. The charger has Voltage and Current....
-
This AC Power Monitor continuously watches the AC power line voltage for both under-voltage and missing cycles. When it detects a total of 5 or 6 consecutive missing half-cycles (50mS, 50/60HZ), it drops a relay and starts a timer. A power contactor is....
-
The 555 frequency can be varied via adjusting the voltage at pin 5. However, the range and linearity of frequency adjustment is very limited. This is a way to greatly improve performance using the inverted 555 timer circuit that was previously posted. Q2 is....
-
To know whether it is freezingyou only need tomeasure the temperature. This has to be done accurately, of course, and therefore we need to choose atemperature sensorthat we have some confidence in. The choice has again been made for a type that we have....
-
This is the circuit diagram of USB powered computer speaker, or it widely known as multimedia speakers for PCs. The circuit has single-chipbased design, low-voltage electrical power supply, compatibility with USB power from computer, simple heat-sinking,....
-
This circuit uses just one IC and a very few number of external components. It displays the audio level in terms of 10 LEDs. The input voltage can vary from 12V to 20V, but suggested voltage is 12V. The LM3915 is a monolithic integrated circuit that senses....
-
The frequency is controlled by the pin 5 of the IC. When the supply is switched ON, the capacitor charges slowly and this alters the voltage at pin 5 of the IC hence the frequenct gradually increases. After the capacitor is fully charged, the frequency no....
-
Light emitting diodes are advan- tageous due to their smaller size, low current consumption and catchy colours they emit. Here is a running message display circuit wherein the letters formed by LED arrangement light up progressively. Once all the letters of....
-
When wired to a ten-digit keypad, the circuit will recognize one 4 digit combination out of a possible 5040 codes. When the programmed four-digit combination is entered from the keypad, in proper sequence, LOCK turns on and Lock Status turns off. The lock....
-
Infrared transmitter and receiver circuit shown in the schematic diagram below can be used as remote control. The transmitter is basically an oscillator circuit, and the frequency can be adjusted using R1 potentiometer (or trimmer pot). This oscillation....
-
The circuit is based on the theory that insects like mosquito can be repelled by using sound frequencies in the ultrasonic (above 20KHz) range. The circuit is nothing but a PLL IC CMOS 4047 wired as an oscillator working at 22KHz. A complementary symmetry....
-
Here we make use of DTMF (dual-tone multi frequency) signals (used in telephones to dial the digits) as the control codes. The DTMF tones are used for frequency modulation of the carrier. At the receiver unit, these frequency modulated signals are....
-
-
-
-
The heart of this circuit is IC No. 555. When the alert sound was working, even though the switch will continue to be the same, the sound still does not stop immediately. But it will stops automatically, when a set time period, Depending on the resistance of....
-
The circuit diagram shows two LT1398`s from Linear Technology used to create buffered color-difference signals from RGB (red-green-blue) inputs. In this application, the R input arrives via 75 coax. It is routed to the non-inverting input of amplifier IC1a....
-
This circuit is used IC number NE555 set up to stable multi vibrator. It produces a frequency rectangular patch of about 100 Hz. Out to pin 3 through C3 and C4. Before the rectifier power section. Both positive and negative DC 2 series. Positive power supply....
-
Here`s a single chip FM transmitter circuit using Maxim semiconductors IC MAX2606. The MAX2606 is a compact, high-performance intermediate frequency VCO specially designed for wireless communication circuits. They have monolithic construction with low-noise....
-
This simple circuit was a presented, it can give power output about 1 watt, when connected to a power supply 9 volt. The advantage of this circuit is that it uses a dual darling ton to increase the size as much as of input impedance about 20 Meg ohm. This....
-
A friend takes an interest to want to try build hi-fi power Amplifier the some one. He likes model class AB, because the sound is good. keen bass good distinct. I chooses this circuit gives him sees, be power Amplifier hi-fi OCL 120W rms sizes really, if use....
-
This circuit can be designed to attenuate signal frequency. Customizable from 1 to 40 dB. If you want to use the band uhf, should be fitted within the frame shield, and C1 to C3 type feeds true. The line should be as short as possible, and the diode should....
-
This circuit will double almost any DC input voltage as well as handling plenty of current. 12 to 24V is just an example. With a few changes, it can also supply any desired output voltage. There are many possible applications. One I can think of would be to....
-
The MAX1846 inverting circuit to implement a switch-mode power supply that provides a -15V at 0. 5A output from a 4. 5V to 12V input. This MAX1846 circuit also adds a few components to the minimum circuit implementation. C20 adds a pole to compensate for the....
-
This is transistor inverter circuit diagram 100watt it sizes are easy circuit. Because of use the all transistor, have no the integrated circuit. It performs to modify from battery 12V be 220V 50Hz signal square wave. By the circuit works with transistor....
-
This is a combination digital clock timer and solar panel charge controller used to maintain a deep cycle battery from a solar panel. The timer output is used to control a 12 volt load for a 32 minute time interval each day. Start time is set using 9 dip....
-
The circuit in Figure 1 is that of a 4-bit asynchronous counter, also known as a `ripple counter`. It consists of 4 J-K flip-flops whose J and K inputs are tied to logic `1`. This connection causes the output of each J-K flip-flop to toggle every time it....
-
The main component of this circuit is an operational amplifier (such as the 741 or 351), configured as an amplifier whose feedback circuit is a diode bridge full-wave rectifier. An ammeter is attached to the rectifier circuit as shown in Figure 1 so that the....
-
This is a monostable multivibrator circuit that employs a single op amp. The main component of this circuit is the 741, a general-purpose operational amplifier. A monostable multivibrator is a timing circuit that changes state once triggered, but returns to....
-
This is a square wave generator circuit. The main component of this circuit is the 741, a general-purpose operational amplifier. This circuit employs a single power supply Vs that can range from +5V to +15V. The square wave output of this circuit is easy to....
-
The circuit shown in Figure 1 is a simple 4-bit digital-to-analog converter. It is actually just a simple op amp summer circuit, i. e. , an operational amplifier configured to output a voltage that is proportional to the sum of the input voltages. The op-amp....
-
This circuit is for a simple LED `bar graph` voltmeter. Each op-amp of the 339 quad operational amplifier is used as a comparator for comparing the input voltage Vin against a corresponding voltage level that`s a fixed proportion of the power supply (9V in....
-
This is a circuit for generating a sine wave from a single operational amplifier. The feedback loop of the op amp in this circuit (741) consists of a twin-T filter connected between its output and its inverting input. Positive feedback for oscillation is....
-
Since the ultrasonic receiver used in this circuit is one designed to vibrate optimally at about 40 kHz, the transmitter paired with this receiver must also transmit 40 kHz waves. When these waves hit the receiver, the receiver vibrates and produces electric....
-
The circuit uses a 555 timer IC configured as an astable multivibrator, i. e. , it generates a continuous signal of a set frequency as long as its reset pin (pin 4) is held high. Since the ultrasonic transducer used in this circuit is one designed to vibrate....
-
Figure 1 shows a circuit for sensing the water level in a tank and turning on or off a water pump accordingly. The main component of the circuit is the CD-4011 Quad NAND gate, three gates of which are used as shown in Figure 1 (gates G1, G2, and G3). G1 is....
-
The circuit was designed based on the operation of Siemens UAA180 as it functions as a LED driver for light band displays for measuring the level of audio signals...
-
This wireless remote control switch production is relatively simple. All components parameters we are testing is complete. Reader component parameters we provide installation can be completed in the production of the first resistive and capacitive components....
-
It's based on a Philips class-H audio amplifier IC and can deliver 36W RMS OR 70W music power, all from a 13.8V supply. Our new Mighty Midget Amplifier can really pack a punch - around 36W RMS continuous into a 4-ohm load when using a 13.8V supply.....
-
An H bridge is a kind of circuit you use to control the direction (and sometimes speed) of an electric motor, using only a single polarity voltage (you need to reverse the way current flows in order to reverse the way the motor rolls). You have 4....
-
Designing a power supply that meets the demands of Power over Ethernet (PoE) and Voice over Internet Protocol (VoIP) applications can be challenging. The low component-count power supply depicted in the figure meets these specifications without the need for....
-
Three devices in a quad Schmitt Trigger and a Flip-Flop make a simple but sensitive proximity sensor..
-
A Pierce (crystal) oscillator intended to provide a reliable clock signal for at least 1 year when powered by battery voltages as low as 2.4 V..
-
Cypress` Dave Van Ess cautions circuit designers about the sloppy overuse of op amps with examples and circuit theory..
-
The transition from diodes to synchronous-rectification (SR) MOSFETs in secondary circuits of flyback converters increases with each new generation of MOSFETs, improving performance at little or no cost penalty. SR MOSFETs can be more efficient than diodes,....
-
This design idea overcomes a significant problem with using photodiodes in fast applications like barcode scanners, CD-ROMs, and DVDs--high output capacitance of the diode. The key part in the circuit is the Analog Devices AD8014..
-
analog-to-digital converters (ADCs) | printed-circuit board (PCB) | microcontroller or digital signal processor (DSP) | total-harmonic-distortion (THD) | ignal-to-noise ratio (SNR)...
-
Author Jim Walker describes a very low cost analog delay line circuit using parts such as the LM311 comparator and 74HC74 D flip-flop...
-
The video circuit illustrated in Figure 1 combines an audio-subcarrier notch filter and group-delay equalization as required by the ITU-470 standard. It also includes an amplitude-adjustment capability for driving an RF video modulator in NTSC applications.....
-
A simple linear voltage-controlled amplifier can be constructed with one op amp and two JFETs (see the figure). The amplifier can achieve an 80-dB dynamic control range with less than ±0.2% linearity error for 0 V ...
-
Over-Temperature Alarm Circuit Uses Common, Inexpensive Components | Negative-temperature-coefficient (NTC) thermistor, ICs...
-
Function generators often play a critical role in the design, testing, and operation of encoders, modulators, demodulators, and measurement instruments. Here`s an inexpensive way to build a bus-controlled sinewave oscillator that has downright low....
-
A simple yet effective circuit to generate a POTS-compatible ringing voltage can be made from National Semiconductor`s LM4871 audio-amplifier IC and a dozen passive components ( see the figure ). This circuit delivers 1 W of sine-wave output at about 70 V....
-
Small inductance changes on the order of 0. 01% can easily be sensed over a wide range with a simple circuit connected to a serial port ( see the figure ). Using a classic Colpitts oscillator interfaced to an eight-pin Atmel ATtiny12-8 microprocessor, the....
-
The figure shows a schematic for an oscillator amplitude-control servo system. The circuit creates a closed-loop system that supplies a fixed and adjustable peak-to-peak amplitude ac signal centered around 0 V. A 1-kHz sine wave, labeled AC_INPUT, is....
-
Temperature-indicator and temperature-based products have generated wide interest. There are numerous applications for such devices with many possible solutions, each with its own advantages and disadvantages. This idea discusses a sensor interface that....
-
Incremental-rotation or linear encoders are very common, but normally they do not provide a direction signal. This design shows an easy way to detect forward or reverse direction. Incremental encoders normally provide two output signals, usually named....
-
TI`s Dafydd Roche completes his 4-part series on sound-bar design with a detailed explanation of clock design for the digital portion of the circuit..
-
Many microcontrollers or PICs will have uncommitted digital-to-analog converter (DAC) outputs that can be used to generate sine waves. But these are generally low resolution (8 to 10 bits), yielding a total harmonic distortion (THD) in the 1% range. Or,....
-
This basic VCO/waveform generator IC circuit includes a voltage follower loop (formed with IC1) and symmetry feedback loop (IC3) to eliminate an asymmetric duty cycle, which would cause distortion at low frequencies. Fig 2. The VCO used in this circuit....
-
This version of the trigger circuit for the stop-motion camera system uses an electret microphone for a sonic input, but the designer can substitute an LED and photodiode pair to create an optical trigger. For a recent home-brew project, I built a....
-
By adding only a few components, you can turn a temperature- and beta-compensated current sink into a common-emitter (CE) amplifier that maintains a stable biased operating point. This Idea for Design will show you how..
-
At the time, I wanted to build The Ultimate Continuity Tester, and I established a wish list of all the features I required: A real continuity tester. Too many multimeters and sounders react at resistances as high as hundreds or even thousands of ohms,....
-
Capacitive sensors are found in a wide range of equipment, from consumer electronics to industrial/process control. Touch buttons are increasingly found in lamps and dimmers. Motion detectors can detect miniscule changes in deflection. Hygrometers indicate....
-
Author Mazi Hosseini describes a simple, low-cost, voltage-controlled current source using two op amps that provides a good range of current and maximum load..
-
-
Below 10 MHz, the realization of engineering models is fairly straightforward and not critically dependent on pc-board layout. At VHF, parasitic circuit elements and spurious coupling can wreak havoc with attempts to achieve performance at low cost without....
-
The R-C twin-tee passive circuit supplies band-reject (notch) filtering to portable applications. It has a circuit Q (loaded) of 0. 25. Satisfactory rejection can be achieved when the bridge is balanced (close tolerances of adjustable components) and the....
-
When supply voltage drops below a minimum threshold, it`s often good practice to disconnect the supply from the system to prevent poor performance or erratic operation. The circuit shown accomplishes this with minimal cost, board space, and complexity ( see....
-
-
Alarm system designs often require circuitry that can detect whether a phone line is active or broken. With this type of design, the primary difficulty is drawing less than 5 µA from the phone line over a line-voltage range of 24 to 58 V as the standard....
-
Frequency shift keying (FSK) is a popular digital modulation technique for data transmission. Some common applications of FSK modulation include both wired and wireless data transmission as well as infrared remote controls for consumer electronic equipment.....
-
-
Before the advent of broadband communications receivers with synthesized oscillators, high-grade, hamband receivers used crystal oscillators and a variable IF to cover relatively narrow (500-600 kHz) frequency segments. The schematic shows a circuit that....
-
This circuit solves the problem of sending data over a cable with no free conductors. The data is OOK (on-off keying) modulated and superimposed on a high-frequency carrier so it can be sent over a low-voltage power supply line..
-
This circuit, a modification of a function-generator circuit, comprises a battery-powered sinewave generator that is continuously adjustable from 100 Hz to 10 kHz..
-
In a number of cases, an inexpensive source of 115-V, 400-Hz power with low distortion is needed for bench tests or mobile applications. This circuit, which uses the Apex Microtechnology PA25 dual power op-amp IC, can be that source...
-
This familiar circuit can be implemented with any rail-to-rail-output comparator or the venerable LMC555. The output period is given by 2log(2)RC = 1. 386RC, and the stability is better than ±100 ppm/ °C against temperature and ±100 ppm/V against....
-
A common piezoelectric alarm, such as the Murata (Smyrna, GA) PKB5-3A shown, has many valuable attributes. It is compact, lightweight, efficient and reliable. However, the loud, high-pitched sound output can be quite irritating in many applications. The....
-
This demodulator is suitable for the quadrature phase-shift keying (QPSK) modulator previously published by the same author, "Novel Low-Cost QPSK Modulator Needs No Adjustments" (electronic design, Sept. 16, 2002, p. 92). Also based on common CMOS logic, it....
-
The second-order multipurpose filter described here can perform as a low-pass, bandpass, high-pass, or notch filter at audio frequencies. What makes this filter unique is that all of its characteristics can be varied independently with potentiometers. In....
-
This circuit, which uses a CD4538 retriggerable monostable multivibrator and a CD4011 NAND chip, can sense fluid levels using a variable capacitance ( see the figure ). Such a sensor can be as simple as two adhesive copper foil strips on a saline or....
-
In typical push-pull driver applications, the npn-pnp transistor pair is alternately turned on and off using a square-wave signal. A simple driver circuit uses an inverter between the V1 and V2 inputs to toggle the output transistors. However, mismatched....
-
Generating sine waves with controlled frequencies over a wide range is difficult when using RC or LC sinusoidal oscillators. However, this performance can be simply created using a wideband digital squarewave oscillator, a counter, and a weighted summing....
-
Signals with a know frequency but unknown phase may be detected using an in-phase and a 90 ° shifted reference signal, as frequently used in lock-in amplifiers, synchronous detectors, and frequency-response analyzers. The 90 °-shifted signal is called the....