Top Circuits Page 201

Just point this small device at the TV and the remote gets jammed. The circuit is self explanatory. 555 is wired as an astable multivibrator for a frequency of nearly 38 kHz. This is the frequency at which most of the modern TVs receive the IR beam. The....

With the preset at its max. the flashing rate of the LED is about 1/2 a second. It can be increased by increasing the value of the capacitor from 10uF to a higher value. For example if it is increased to 22uF the flashing rate becomes 1 second. There is also....

Here is a simple circuit which can be used for decoration purposes or as an indicator. Flashing or dancing speed of LEDs can be adjusted and various dancing patterns of lights can be formed. The circuit consists of two astable multivibrators. One....

This circuit uses three easily available 555 timer ICs. All three work as astable multivibrators. The first 555 has an on period and off period equal to 1 sec. This IC controls the on/ off periods of the other 2 555s which are used to flash two bulbs through....

This circuit lights up ten bulbs sequentially, first in one direc- tion and then in the opposite direction, thus presenting a nice visual effect. In this circuit, gates N1 and N2 form an oscillator. The output of this oscillator is used as a clock for BCD....

The circuit of automatic emergency light presented here has the following features: 1. When the mains supply (230V AC) is available, it charges a 12V battery up to 13. 5V and then the battery is disconnected from the charging section. 2. When the battery....

You can test the board now. For example set the DIP switch to Switch1 ON, Switch2 OFF (15 sec delay) & switch3 ON, switch4 OFF (4 rings to activate half for switching ON). If you want to switch ON relay 1 (connected to RB0 of main circuit) then you have to....

Voltage variations and power cuts adversely affect various equip- ment such as TVs, VCRs, music systems and refrigerators. This simple circuit will protect the costly equipment from high as well as low voltages and the voltage surges (when power resumes). It....

Ahigh 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....

Colpitts oscillator. Its frequency depends on the capacitance of the vary cap diode. The center frequency is changed by varying the biasing voltage of the vary cap through the 47K pot. You can use a 75cm telescopic antenna or simply a length of hook-up wire.....

The RF oscillator using the inverter N2 and 10. 7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3. Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th....

The miniature transmitter module shown in Fig. 1, which just measures 34 mm x 29 mm x 10 mm, can be used to operate all remote control receiver-cum-switch combinations described in this project. A compact 9-volt PP3 battery can be used with the transmitter.....

Here is a circuit of a remote control unit which makes use of the radio frequency signals to control various electrical appliances. This remote control unit has 4 channels which can be easily extended to 12. This circuit differs from similar circuits in view....

The given circuit, when connected in parallel to a telephone, dis- plays the number dialled from the telephone set using the DTMF mode. This circuit can also show the number dialled from the phone of the called party. This is particularly helpful for....

The circuit shown here is used to switch on a lamp when the tele- phone rings, if the ambient light is insufficient. The circuit uses only two ICs and it can be implemented very easily. A light dependent resistance (LDR), with about 5 kilo-ohms resistance in....

Many a times one needs an ex- tra telephone ringer in an ad- joining room to know if there is an incoming call. For example, if the telephone is installed in the drawing room you may need an extra ringer in the bedroom. All that needs to be done is to....

In this circuit, a simple calculator, in conjunction with a COB (chip-on-board) from an analogue quartz clock, is used to make a telephone call meter. The calculator enables conversion of STD/ISD calls to local call equivalents and always displays current....

A high-input-resistance op-amp, a bridge rectifier, a microammeter, and a few other discrete components are all that are required to realise this versatile circuit. This circuit can be used for measurement of dc, ac rms, ac peak, or ac peak-to-peak voltage....

Here is a handy gadget for test- ing of infrared (IR) based re- mote control transmitters used for TVs and VCRs etc. The IR signals from a remote control transmitter are sensed by the IR sensor module in the tester and its output at pin 2 goes low. This in....

For simple electronic circuits, it may be sufficient to get a qualitative insight on dedicated electrical signals. This interface circuitry allows to use the line-in input of a standard PC soundcard to be used as a 2-channel oscilloscope. This setup does not....

The first timer IC555 creates a negative trigger signal of approximately 45Hz (a trigger impulse every 22ms, DO NOT exceed 50Hz for proper servo function). The second timer IC555 modulates a positive square signal from 0. 9ms to 2. 1ms every 22ms, a method....

This circuit uses a digital pot to allow the microcontoller to automatically adjust the gain of the circuit to suit the ambient audio volume, but you could replace this with a standard pot if this isn`t needed. The low pass filter is a copy of Graham....

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This circuit controls five outputs 220V. Potentiometer change speed and a switch select effect (one direction or both directions). The circuit has a divider by 10 (4017), a transistor oscillator (2N2646), the power stage and power supply. Each pulse on pin....

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Take a good capacitor, around 100 or 1000 microfarads, and connect a small resistor, 10 or 5 ohms, in series with it. Connect to the meter and adjust that pot until the meter reads the resistance of that resistor. Repeat with other capacitors and resistors....

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this project use PIC18F25K20 microcontroller to detect if the sensor change state and it will emit a sound from the speaker or piezo, the MCU also detect the voltage of the battery in the startup, the algorithm it s very simple use an interrupt on change to....

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Completely safe operation is guaranteed due to protection against DC and AC short circuit between all pins and ground, thermal over-range, load dump voltage surge up to 40V and fortuitous open ground. ..

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At this circuit you can give a variety of utilities, from an alarm, to open a door, turn on a light in the garden or courtyard, and so on. Your imagination has the last word. HOW IT WORKS: The operating principle is based on the properties of a photoelectric....

This 12V power inverter circuit can be used to power small power devices that need a 240 volts. This 12V power inverter circuit is very useful when you want to use a 240 volts consumer powered by a 12 volts car battery. In contrast to the usual feedback....

This 555 timer circuit temperature monitoring system electronic project can be monitor temperature in up to four points. Using this 555 timer circuit temperature monitoring system electronic project can be choose if the alarm should be triggered when....

This 555timer clap switch circuit electronic project is designed using some common electronic parts. This 555 timer clap switch circuit electronic project operates from a distance of up to 10 meters from the microphone. Signal from microphone is amplified by....

This door minder electronic project is based on a 555 timer circuit and uses an IR beam to monitor door and passage-ways or any other area. When the IR beam is broken a relay is tripped which can be used to sound a bell or alarm. This door minder electronic....

This LED Flasher circuit is based on the 555 timer IC. The LED Flasher circuit diagram is very simple and require few external components. When the circuit is working the red LEDs will flash at a set frequency one by one like at the railway crossing....

Using this 555 timer DC motor control electronic project you can control speed of a 6 volts DC motor, by simply rotate left or right the 50 k potentiometer. ..

Speed regulation is accomplished by sensing the motor current with R17 and using it as positive feedback to compensate for motor resistance loss. The gain pot should be set to a point just below the point where the motor speed oscillates. After finding this....

This door open alarm electronic project is designed using an linear hall effect device and a 555 timer circuit. This door open alarm alarm electronic project is based on the TL3103 linear hall effect device used for detecting the angle of rotation. The....

This smoke detector is designed using 555 timer circuit and some common electronic components. The photo interrupter module is used as the smoke detector, while timer 555 is wired in astable configuration as an AF oscillator for sounding alarm via a....

This voltage doubler circuit use a 555 timer integrated circuit wired as an astable mutivibrator. This voltage doubler circuit can deliver only up to 50mA output current and above that current limit the output voltage will be reduced. The actual output....

The water sensor circuit is based on a 555 timer circuit and come common electronic components. The water sensor is made by two metal electrodes arranged very close that a drop of water (liquid) will bridge them. If the liquid ( water ) is very pure you may....

A very high power and efficiency 100w power amplifier electronic project can be designed using the STK404 audio power amplifier hybrid ICs that consist of optimally-designed discrete component power amplifier circuits that have been miniaturized using....

This 2 channels audio mixer is based on the 2n3904 transistors which forms 2 preamplifiers. The first preamplifier of the audio mixer has a high gain and can be used for microphone input, and the second one can be used to control the input of the audio....

This audio distribution electronic project circuit diagram is designed using the TL064 or TL06 operational amplifiers and some other common electronic parts. ..

BA3822 five-point stereo graphic equalizer integrated circuit has two channels, and the five center frequencies for each channel are independently set using external capacitors. These IC feature a wide operating power supply voltage range (VCC = 3. 5V to....

This electret microphone amplifier is designed using common electronic components. This microphone amplifier uses an electret microphone capsule, but can be an dynamic microphone, which have a low resistance. This circuit requires a supply voltage between 5....

This microphone preamplifier electronic project is based on transistors and is capable of about 70dB or more gain at audio frequencies. Gain of this circuit is approximately equal to the product of the hfe of the both transistors times in the ratio of the....

Using the LA4440 audio amplifier IC can be designed a very simple stereo power audio amplifier electronic project, that will provide a 6 watt output power into a 8 ohms load. Some features of this audio amplifier IC are: minimum number of external parts....

This volume controller equalizer electronic project is designed using LM1036 DC tone volume controller with volume and balance circuit for stereo applications. The four control inputs of the LM1036 volume controller provides control of the bass, treble,....

This LM12 audio amplifier circuit will provide a high output power on a 8 ohms or 4 ohms load impedance. The maximum output power delivered by this LM12 audio amplifier is around 60 watts on a 4 ohms load and 100 watts on a 4 ohms load on each channel. A....

A very simple 20 watt amp electronic project can be designed using the LM2005 dual high power amplifier, designed to deliver optimum performance and reliability for automotive applications. LM2005 20 watt amp has a high current capability (3. 5A) that....

Using the LM2876 audio power amplifier circuit can be designed a very simple high efficiency power audio amplifier capable of delivering 40W of continuous average power to an 8 © load with 0. 1% THD+N from 20Hz 20kHz. The LM2876 audio power amplifier circuit....

This simple microphone preamplifier is based on the LM318 op amp. The LM318 op amp is operated as a standard non-inverting amplifier. Resistor R1 provides an input path to ground for the bias current of the non-inverting input. The combination of R2 and C2....

Using LM380 and few external components can be designed a simple audio amplifier that has many features like : wide supply voltage range, 150k © input impedance, low distortion, 1. 3A current capability. ..

Using LM386 power amplifier designed for use in low voltage consumer applications can be designed a very simple voice amplifier with variable gain and volume control. The gain is internally set to 20 to keep external part count low, but the addition of an....

This LM3886 amp electronic circuit project is capable of delivering 68W of continuous average power into a 4ohms load and 38W into 8ohms with 0. 1% THD+N from 20Hz 20kHz. The performance of the LM3886 amp, utilizing its Self Peak InstantaneousTemperature (....

using the LM3915 monolithic integrated circuit can be designed a very simple audio power level meter that senses analog voltage levels and drives ten LEDs, LCDs or vacuum fluorescent displays, providing a logarithmic 3 dB/step analog display. One pin of the....

This microphone preamp schematic electronic circuit project is designed using the OP37 operational amplifier manufactured by Analog Devices and is effective, fixed-gain transformerless microphone preamp which amplifies differential signals from low impedance....

Using TBA820M audio amplifier integrated circuit can be designed a very simple audio amplifier circuit using few electronic parts. This audio amplifier electronic project has a very high gain as can be hear under water sounds. The TBA820M is a monolithic....

The TDA1029 is a dual operational amplifier (connected as an impedance converter) each amplifier having 4 mutually switchable inputs which are protected by clamping diodes. Signal-sources switch can be made in various mods : Electronic parts required by this....

This TDA1514 audio amplifier circuit design electronic project is capable to provide a high audio power output using a specialized audio IC and other few common components. The TDA1514 audio IC is manufactured by Philips Semiconductor and is capable to....

The TDA1519 circuit can deliver 2x6 watts output power. TDA1519 is an integrated class-B dual output amplifier in a 9-lead single in-line (SIL) plastic medium power package is primarily developed for car radio applications. ..

This TDA2030 200 watt amp low cost audio power amplifier can deliver high output audio power up to 200 watts on a 2 4 ohms load impedance. This 200 watt amp high power audio amplifier is build around the TDA2030 audio amplifier IC which normally can deliver....

This TDA2030 35 watt audio amplifier circuit project is designed to provide an output power of 35 watts on to a 8 ohms load. The TDA2030 is a monolithic IC in Pentawatt package intended for use as low frequency class AB amplifier. The TDA2030 provides high....

A very simple multiway active speaker audio systems can be designed using the TDA2030 audio IC. This TDA2030 active speaker audio system circuit is designed to provide the best possible acoustic performance since each loudspeaker is specially designed and....

This TDA7056 power audio amplifier electronic circuit diagram project will provide a maximum output power of 1 watt into a 8 ohms load using a 6 volts power supply, or a maximum output power of 3 watts into a 16 ohms load using a 11 volts power supply. As....

Using TDA7250 audio driver manufactured by SGS Thomson, can be designed a very simple high power audio amplifier electronic project using few external electronic parts. This TDA7250 audio amplifier electronic project can be used using a 4 ohms load or a 8....

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In practical cases a series resistance has always to be inserted, having it the double purpose of limiting the current at pin 7 and to smooth down the stand-by ON/OFF ..

The input capacitor is for the low frequency cut-off and the standard value for the input capacitors is 0. 1uF ( the cut-off for this value is amount to 16Hz). ..

A very simple class B power amplifier can be designed using TDA8560 audio IC. The TDA8560 amplifier has an internally fixed voltage gain for excellent channel balance. This audio amplifier electronic project will provide a dual 40 watt output power. This....

This electronic circuit diagram is an audio power amplifier based on TDA8571J integrated circuit, class-B output amplifier with four amplifiers in a BTL configuration, each with a gain of 34 dB. Main features of the TDA8571J amplifier circuit are : high....

This high power class D audio amplifier electronic project is designed using the TDA8920BTH audio power amplifier IC. This power amplifier audio IC has a very high efficiency with very low dissipation, providing a very high output power. The typical output....

This audio mixer circuit diagram electronic project is designed using few common electronic components. This audio mixer circuit project has two input channels. The input signal can be independently controlled using the R1 and R2 variable resistors. The R3....

Using the UM3561 integrated circuit can be designed various alarm systems using few electronic parts. This UM3561 alarm electronic project require few electronic parts and is powered from a simple 3 volts dc power supply. ..

This voice changer circuit diagram electronic project is designed using the RTS0072B single chip CMOS LSI designed for voice changer applications, which can transpose or distort one voice into another voice by encoding the input audio signals in normal speed....

As you can see in this schematic circuit this battery charger has extreme few components, but is doing a very good job. When power is applied to the circuit the SCR1 is off, so there is no bias-current path to ground. The LM317 is connected to the battery....

This cell phone charger circuit diagram electronic project is based on the FSEZ1307 third-generation primary side regulation (PSR) PWM controller integrated circuit. The FEZ1307 cell phone charger can be used for battery chargers applications for devices....

A very simple 3. 25W CV/CC charger can be designed using LinKSwitch | family IC manufactured by Power Integrations. This electronic circuit project is designed to provide a 5 volts output at a maximum current of 650mA. This 3. 25W CV/CC charger, needs to be....

A very simple and efficiency Lithium battery charger and monitoring system, can be designed using the LTM8061 integrated circuit, designed by Linear Technology. The LTM8061 IC is a high efficiency 32V, 2A Module standalone Lithium battery charger optimized....

A very simple 5 volt constant voltage, constant current (CV/CC) universal-input power supply for cell phone or similar charger applications can be designed using the LNK616PG product from the LinkSwitch-II family. As you can see in the circuit diagram, this....

This simple wind Charger circuit electronic project is designed using the LTC1042 monolithic CMOS window comparator, manufactured by Linear Technology. This Wind charger circuit electronic project use the wind power to produce the energy required to charge....

For the MAX712 charger is needed a power supply with a output voltage with at least 1. 5V higher than the maximum battery voltage. Charge completion is determinate by a voltage-slope detecting analog-to-digital converter, timer, and temperature window....

Using the MAX8844 lithium ion charger IC released by Maxim Semiconductors you can design an very simple and efficiency charger circuit for charging a single cell lithium-ion battery. The MAX8844 lithium ion charger integrate a current-sense circuit, MOSFET....

The DC input for this charger ic operates from 4. 15V to 16V with up to 20V protection, while the USB input has a range of 4. 1V to 6. 3V with up to 8V protection. ..

Using the LTC4060 integrated circuit, can be designed a very simple smart NiMH battery charger electronic project. This electronic charger circuit project is a complete fast charging system for NiMH or NiCd batteries. This NiMH battery charger circuit....

As you can see in circuit diagram, this portable solar charger circuit, is based on a LM358N operational amplifier and one transistor. This regulator provide a constant 2. 4 volts DC and can be used for powering small devices that needs to be powered from....

This micropower multifunction power management integrated circuit (PMIC) is designed using LTC3554 manufactured by Linear Technology Corporation and is a solution for portable Li-Ion Polymer battery-based applications. This micropower multifunction power....

A simple Solar powered battery charger, photovoltaic charger circuit can be designed using LTC4071 Li-Ion/Polymer Shunt Battery Charger System with Low Battery Disconnect. When VCC reaches the programmed float voltage (4. 1V with ADJ floating) then the....

This UC3906 battery charger circuit controller contains all of the necessary circuitry to control the charge and hold cycle for sealed lead-acid batteries. The UC3906 battery charger circuit is specifically designed to provide the proper charging voltage and....

Using MAX641 integrated circuit, manufactured by Maxim IC, can be designed a very simple step-up converter using few electronic components. This step-up high voltage converter electronic projects allows a maximum output current up to 1A. Low battery voltage....

Using the LM3410 constant current LED driver is a monolithic IC we can design, many high efficiency and low cost lights, using just few electronic components. The LM3410 utilizes current-mode control and internal compensation to provide high-performance over....

A very simple white led driver schematic circuit can be designed using the EL7513 constant current boost regulator specially designed for driving white LEDs. It can drive 4 LEDs in series or up to 12 LEDs in parallel or series configuration and achieves....