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Radio Circuits

Stereo decoder circuit

Stereo decoder circuit. In FM stereo transmission left and right channels are algebraically encoded into sum (left + right) and difference (left-right) signals. This is done in order to make the mono FM receivers compatible with the stereo transmission. The mono receiver will reproduce the summed left and right channel and the listener will hear […]

Power Supplies

Transformerless switch mode power supply circuit

12V/120mA switch mode power supply circuit Transformer less switch mode power supplies have become very popular these days. The circuit shown below is of a 12V/120mA output, 85 to 230V AC input transformerless switch mode power supply using LNK304 IC. Applications of a power supply based on this IC includes hand held devices, timers, small

Power Supplies

LDO regulator

LDO regulator / low dropout regulator LDO regulator means low dropout regulator. An LDO voltage regulator is just a DC linear voltage regulator which can be operated with a very small input-output voltage differential. This input output voltage differential is called dropout voltage. In simple words dropout voltage is the voltage dropped by the regulator

Power Supplies

Few switching regulator circuits

Switching regulator . Switching regulators work by drawing small amounts of energy from the input source and transferring it step by step to the output. This task is attained by using an electronic switch (operating at a predetermined frequency) which works like a gate between the input energy source and the output. This gate controls

Signal Conditioners

Sample and Hold Circuit – How to Make

Sample and hold circuit using op-amp As the name indicates , a sample and hold circuit is a circuit which samples an input signal and holds onto its last sampled value until the input is sampled again. Sample and hold circuits are commonly used in analogue to digital converts, communication circuits, PWM circuits etc. The

Power Supplies

Three phase rectifier using 20L6P45

Three phase bridge rectifier using 20L6P45. Three phase full wave rectifier circuit is an advanced power rectifier circuit mostly used for industrial DC applications. This module basically has 3 phase inputs and a single DC output. Most of the industrial power supplies such as DC motor drives, welding units, etc are used these kinds of

Power Supplies

Few LM317 voltage regulator circuits

Some circuits based on LM317 voltage regulator Few useful circuits using the voltage regulator IC LM317 is shown here. LM317 is a three terminal voltage regulator IC from National Semiconductors. The IC is capable of delivering up to 1A of output current. Input voltage can be up to 40V and output voltage can be adjusted

Home Circuits, Industrial Circuits

Water level Controller

Water level controller circuit Note:- We have developed another water level controller circuit using micro controller AT89S51 from Atmel. If you are interested, read that too :- Water level controller using micro controller Are you familiar with the basics and the different applications of the 555 timer IC. If not, we recommend you 3 books

Sensor Circuits

Liquid level indicator

LM1830 based liquid level indicator circuit. LM1830 is a monolithic integrated circuit that can be used in liquid level indicator / control systems. Manufactured by National Semiconductors, the LM1830 can detect the presence or absence of polar fluids . Circuits based on this IC requires minimum number of external components and AC signal is passed

Conversion Circuits

Frequency to voltage converter

Frequency to Voltage converter circuit based on TC9400 IC. Description. A very simple and low cost frequency to voltage converter based on the TC9400 IC from Microchip is shown here. TC9400 can be either wired as a voltage to frequency converter or frequency to voltage converter and it requires minimum external components. The functional blocks

Audio Circuits

Passive tone control circuit

Tone control circuit. This is just another circuit designed by Mr. Seetharaman Subramanian and time it is a high quality passive tone control circuit that has an overall gain of around 25 with 20dB boost and cut. This circuit needs minimum number of components, is very cost effective and most of the components required can

Lighting Circuits

LED lamp circuit from scrap

Power saving LED lamp from your scrap box. This circuit is designed by Mr Seetharaman Subramanian and we are very glad to publish it here. In this article he is showing a method to convert a broken/defunct CFL into a LED based power saving light. This is just a LED lamp circuit that can be

Audio Circuits

Few Transistor amplifier circuits

This article is a list of various types of amplifier circuits built using Transistors alone.This includes a Class AB amplifier using 4 transistors, then we have a headphone amplifier circuit and finally a low power amplifier using transistor. This article is solely dedicated to publish more transistor amplifier circuits. So you may keep visiting this

Power Supplies

12V to 24V DC DC converter

12V to 24V converter. Description. There are many instances where we require 24V DC from a 12V source. I also once faced a situation like this when I decided to fit a small transistorised stereo amplifier which operated from 24V DC in my car. I found this circuit to be well enough for my application.

Audio Circuits

Intercom circuit

Intercom circuit with ringer Description. A simple intercom circuit designed based on transistors is shown here. This intercom circuit does not require a changeover switch and you can use it just like a telephone and a ringer circuit is also included. IC1 UM66 and transistor Q1 forms the ringer section. When pushbutton switch S1 is

Radio Circuits

AM receiver circuit using MK484

MK484 AM receiver circuit  Description. A simple AM receiver circuit based on the MK484 AM receiver IC from Rapid Electronics Ltd is shown here. MK4844 is a monolithic integrated circuit that has all the necessary sections of a AM receiver like RF amplifier, detector, AGC etc. The IC is available in TO92 package and requires

Lighting Circuits

Automatic night light

Automatic night light circuit Description. A cheap and simple automatic night light using few transistors and NE555 timer is shown here. The circuit will automatically switch on the AC lamp when night falls and the lamp will be automatically switched off after a preset time. The working of this night light circuit very simple. An

Power Supplies

6 to 15V DC to DC converter

6 to 15V DC to DC converter using LM2585 Description. A very efficient 6V to 15V DC to DC converter using LM2585 is shown here. LM2585 is a monolithic integrated voltage converter IC that can be used in various applications like flyback converters, boost converters, forward converters, multiple output converters etc. The circuit requires minimum number

Radio Transmitters

Stereo FM transmitter using BA1404

Stereo FM transmitter circuit using BA1404. Notes. A high quality stereo FM transmitter circuit is shown here. The circuit is based on the IC BA1404 from ROHM Semiconductors. BA1404 is a monolithic FM stereo modulator that has built in stereo modulator, FM modulator, RF amplifier circuitries. The FM modulator can be operated from 76 to

Power Supplies

12V to 120V DC DC converter

Description. A simple 12V to 120V DC DC converter circuit is shown here. The circuit consists of two stages firstly a basic inverter stage and then a rectifier plus filter stage. IC1 NE555 is wired as an astable multivibrator operating at a frequency of 100Hz and it can be adjusted using the preset R1. Output

Power Supplies

5V boost converter

5V Boost Converter circuit . Description. A simple 5V boost converter using LTC3440 is shown here. LTC3440 is a highly efficient DC to DC converter that can be operated from input voltages below, above or equal to the output voltage. In terms of synchronous rectification, LTC3440 provides up to 96% efficiency and up to 600mA

Power Supplies

Buck boost converter circuit

Buck Boost converter circuit using LTC3440 Description. A very efficient buck boost converter circuit is shown here. The circuit is based on the LTC3440 buck boost regulator IC from Linear Technology. The LTC3440 requires only one inductor and provides up to 96% efficiency. There is no need of Schottky diode for applications where output voltage

Motor Related

DC motor controller

DC motor control circuit using NE555 Are you familiar with all the applications of 555 timer circuits? If not, we can help you. We all know that for better understanding, the best source is an authenticated book on the subject. CircuitsToday presents an online store which has reviews on 3 books that are considered to

Amplifier Circuits, Audio Circuits

6 watt Hi Fi audio amplifier using TDA2613

TDA2613 Hi Fi audio amplifier Description. A 6 watt audio amplifier circuit using TDA2613 is shown here. TDA2613 is an integrated Hi-Fi  audio amplifier IC from Philips Semiconductors. The IC is switch ON / switch OFF click proof, short circuit proof, thermally protected and is available in 9 pin single in line plastic package. In

Audio Circuits, Automotive Circuits

Car stereo amplifier circuit using TDA2040

Car Audio Amplifier Circuit: Given below is a car stereo amplifier circuit using  audio amplifier IC – TDA2040 Description of the circuit: A car stereo amplifier circuit using TDA2040 is shown here. TDA2040 is a monolithic integrated audio amplifier that operates in Class AB mode. The IC has built in circuitry for short circuit protection

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