Fun & Game Circuits, Tone generator circuits

Whistle to beep circuit

Description. This simple circuit produces a beeping sound that lasts for around 3 seconds whenever you make a whistle. The CMOS Hex inverter CD4049 is the heart of this circuit. Out of the six inverters in CD4049, U1a is wired as an audio amplifier which amplifies the signal picked up by the microphone M1.The U1b […]

Audio Circuits, Automotive Circuits

24W amplifier using TDA1516

Description. Here is the circuit diagram of a simple 24W mono amplifier using IC TDA1516.The TDA1516 is an integrated class B power amplifier in a 13 pin SIL package. The IC has many useful features such as short circuit protection, load dump protection, thermal protection, reverse polarity protection etc. Here the IC is wired in

Motor Related

PWM motor speed controller

Description. This circuit is designed as per a request made by Mr Vinoth from India. His requirement was a 12V/5A DC fan motor controller. I think this circuit is sufficient for this purpose. Quad 2 input Schmitt trigger IC CD4093 is the heart of this circuit. Out of the four Schmitt triggers inside the 4093,

Power Supplies

Regulated dual power supply circuit

Dual Power Supply Circuit Description The circuit given here is of a regulated dual power supply that provides +12V and -12V from the AC mains. A power supply like this is a very essential tool on the work bench of an electronic hobbyist. The transformer T1 steps down the AC mains voltage and diodes D1,

Automotive Circuits, Battery Circuits

Car battery charger

Description. Given below, is a very simple circuit that can be used for charging car batteries. In this circuit there is facility for monitoring the charging current and voltage. The circuit is based on the IC MC78T12ABT from Freescale.The IC is nothing but a 7812 in TO-3 package with 3A capacity. The transformer T1 steps

Fun & Game Circuits

Digital dice circuit

Description. This is a simple and easy to construct digital dice circuit. The circuit is based on a single IC, CD4060B.The dice consists of six LEDs marked D1 to D6.The number of LEDs glowing indicates the numeral. The heart of this circuit is 14 stage binary ripple counter IC CD4060B.The IC also has a built-in

Lighting Circuits

Simplest lamp flasher circuit.

Description. This is a very simple lamp flasher circuit that uses only three components (a capacitor, relay and one resistor) other than the lamp. The working of the circuit is very straight forward. When the power is switched ON the capacitor C1 charges through the resistor. When the voltage across the capacitor is sufficient, the

Motor Related

Bi-directional motor

Description. This is a simple and easy to construct circuit that can be used to provide a bidirectional drive to a DC motor. The circuit operation is straight forward. Output of an astable mutivibrator based on IC1 (NE555) is used to control the relay RL1 driving the motor. The motor is connected between the two

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Test & Measurement Circuits

Transistor tester circuit

This article discusses various circuits that can be used to test a Transistor, both NPN and PNP. We have structured this article into two circuits. If you have any doubts about any section please ask through comments. 1. Transistor Tester built using Transistors 2. Simple Transistor Tester (Contains both Circuit Diagram and PCB Lay Out)

Lighting Circuits

Automatic emergency light

Description. This is a simple automatic emergency light which remains OFF when the mains power is available and switches ON when there is a power failure. When mains power is available, it is stepped down by transformer T1, rectified by diodes D1&D2, filtered by the capacitor C2 and regulated by the 9V regulator IC 7809

Testing Components

How to test an SCR

Testing SCR using a multimeter. A multimeter can be used to test SCRs quite effectively. The first procedure is to check the diode action between the gate and cathode terminals of the SCR. This test is just like what you have done in the case of testing a silicon diode (see testing a silicon diode).

Testing Components

How to test a triac.

Testing triac using a multimeter. A multimeter can be used to test the health of a triac. First put the multimeter selector switch in a high resistance mode (say 100K), then connect the positive lead of multimeter to the MT1 terminal of triac and negative lead to the MT2 terminal of triac (there is no

Testing Components

How to test a diode

Diodes are one of the components that can be tested very easily.Ordinary diodes as wells as Zener diodes can be checked by using a multimeter. While testing a diode the forward conducting mode and reverse blocking mode has to be tested separately. Testing ordinary diode using a digital multimeter. To check an ordinary silicon diode

Light Related

LED ramping circuit.

Description. In this circuit the intensity of LED will vary in a ramping fashion. The circuit consists of three ICs: Two 555 timer ICs and one LM393 op-amp. IC1 and IC2 are wired as oscillators to produce 10 KHz and 1 Hz frequencies respectively.These two frequencies are given to the inputs of the op-amp LM393.LM393

Sensor Circuits, Temperature Related

Zero degree Celsius alarm

Description. This simple circuit will produce an alarm whenever the temperature falls below zero degree. A thermistor is used here to sense temperature. The op-amp LM7215 is used to compare the reference voltage and voltage from the thermistor network. Reference voltage is given to the non inverting input (pin3) of the IC and voltage from

Battery Circuits

Battery charging indicator circuit

Description. This simple circuit can be used to monitor whether a battery is charging or not. The voltage comparator IC LM393 is the heart of this circuit. The LED D1 will remain ON whenever there is at least 25 milli ampere current flowing to the battery. This particular circuit is designed for a 12V battery

Power Supplies

1.3V Power supply

Description. This 1.3V power supply can be used as replacement for the 1.3V Mercury Cell in any circuit. When the input 5V is given to the circuit, the  voltage drop across  zener diode D1 will be around 2V.The diode D2 will drop a 0.7 V from the 2V volt and the remaining 1.3V will be

Power Supplies

Soft start power supply using L200

Description. Here is the circuit diagram of a simple soft start power supply using the well known IC L200.The L200 is a monolithic IC that can be used for voltage and current regulation. The built-in features such as thermal shut down, over current protection and input over voltage protection makes this IC nearly indestructible. When

Power Supplies

Soft start Power supply circuit.

Description. Here is the circuit diagram of a simple soft start power supply using the well known voltage regulator IC LM317.Here the IC is wired in soft start mode in which the output of the IC gradually increases to the desired output voltage .When the input voltage is given to the IC , the capacitor

UPS

Simple UPS

Description. This is the circuit diagram of a simple UPS that can deliver 12V unregulated and 5V regulated DC. The transformer T1 steps down the mains voltage to 12V AC and then the bridge B1 rectifies it. The rectified signal is smoothed by the capacitor C1.When the mains supply is available the battery will be

Power Supplies

12V 15A voltage regulator

Description. Here is the circuit diagram of a powerful 12V regulator that can deliver up to 15 A of current.The common voltage regulator IC 7812(IC1) is used to keep the voltage at steady 12V and three TIP 2599 power transistors in parallel are wired in series pass mode to boost the output current. The 7812

Gadget Reviews, Tech News

Lenovo IdeaCentre A600-Review

“Sleek&Sexy” in design-thats what Lenovo IdeaCentre A600 is @ first look. This revolutionary desktop in the age of tablets and notebooks features 21.5″ screen for multimedia-holics along with Blu-Ray disc and other usual system components. Features are: Processor: Intel Core 2 Duo Memory: 4GB of DDR3 memory Hard Disk: Upto 1TB (available) Additional Luxury: In

Audio Circuits

3 Input mic mixer circuit

Description. Here is a simple 3 input mic mixer circuit using the popular uA 741 ICs. Four 741s are used here.IC1, IC2, IC3 are used as preamplifiers. They produce a gain of around 40 decibel to the individual input signals. The IC4 is wired as a summing amplifier to add the signals from three preamplifiers.IC4

Microcontrollers, Tech News

Six pin Microcontrollers from Atmel-AVR ATtiny10

Six pin Microcontrollers from Atmel-AVR ATtiny10 The latest AVR ATtiny10 is highly suitable for large volume market applications. AVR ATtiny10 has 1kilobytes of programmable flash memory, 32 bytes of internal Static Ram,  8-bit Analog to Digital converter, a 16-bit timer with Pulse Width Modulation, 12 MIPS of processing throughput and an analog comparator.Using the AVR

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