Description. Many fire alarm circuits are presented here,but this time a new circuit using a thermistor and a timer to do the trick. The circuit is as simple and straight forward so that, it can be easily implemented. The thermistor offers a low resistance at high temperature and high resistance at low temperature. This phenomenon […]
Description. No big deal here! You can make a decent power amplifier using just three transistors. All components used here can be obtained from your electronic junk box. Also you just need a 9V transistor radio battery to power this circuit. The circuit is ideal for a pocket radio or other hand held audio equipments.
Description. This straight forward circuit will protect electrical appliances from over voltage as well as under voltage. The circuit also produces an alarm when the power supply comes back. An ideal circuit for home to protect your valuable equipments from voltage fluctuations. The same circuit with some modifications can be used to make a automatic
Description. A simple sawtooth wave generator circuit for generating a saw tooth wave form using a NE555 IC is given below. The frequency of the wave form can be varied by using a POT. The capacitor C, resistor R and zener diode forms a constant current source for charging of the capacitor. When the voltage
Description. Here is a simple variable frequency circuit based on timer NE555. Here NE55 is wired as an astable multivibrator, whose output frequency can be varied by varying a potentiometer. This circuit is a must in the work bench of a electronic hobbyist. Frequencies ranging from several Hz to several KHz can be obtained using
Description. A variety of humidity tester circuits are available, but this is a circuit which is as simple as possible. Using only a transistor, LED and few resistors, this circuit can be used to check the humidity level of materials like soil, paper etc. When the humidity in a substance increases the current conducted throughÂ
Description. A simple scoring game circuit that can be used for all occasions when a dice is needed.The circuit is based on a NE555 timer,a 74LS192 counter,a74LS247 decoder and a & segment LED display.The timer IC1 will produce the clock for the counter IC(IC2) whose frequency is determined by R1 and C2.When S2 is pressed
A simple Light to Frequency Converter Introduction. Here is the circuit diagram of a effective light to frequency converter circuit that can be used for variety of applications such as light intensity measurement,fun etc. The circuit is based on TLC555, the CMOS version of famous timer IC NE 555. A photo diode is used for
Transformerless power supply Circuit Description Here is a low cost and simple circuit that can be used to power up small electronics devices. The power is directly tapped from the mains via resistor R1. D1 rectifies the voltage and C1 and C2 are used to filter the output. The zener diode D2 will regulate the
Remote control tester Circuit Description This is a simple remote controller tester circuit based on infrared sensor IC TSOP 1738. When the IR waves fall on the sensor it output changes to low state. This makes the transistor Q1 (BC558) ON and LED will blink according to the code contained in the signal. So for
12 Watts Transistor Amplifier Circuit Description The circuit shown below is not at all expensive as the amplifier contains only an op-amp and four transistors (easily available from your electronics junk box). Here the op-amp used is uA 741 which produces the required gain. The four transistors are wired as complementary Darlington’s which produces the
Dual Tone Train Horn Circuit – Description A dual tone train horn simulator circuit can be made using two NE 555 timers connected in cascade. Here instead of using two NE 555 timers a single NE 556 timer is used which is nothing but cascading two 555’s in one package and each timers works independently.
What is a sound level meter? A sound level meter is handy equipment used to display sound levels. There are wide ranges of these devices; some show a digital numerical output of how many decibels of sound are created while some other shows a bar graph indicator (the decibel meter you see in mission impossible
In this project, let’s learn about a simple Stereo Amplifier Circuit. This simple circuit is designed using 4 class B audio amplifier IC’s from Philips – namely TDA1554. Amplifier circuits are usually a pain to design, as you’ve to factor many elements into consideration. The Design of Stereo Amplifier Circuit Here is the circuit diagram of
All audio amplifiers have some mechanism to increase and decrease volume. Most such mechanisms involve mechanical parts like a potentiometer. Here this project is to create an audio controller that works digitally. This is a very simple project which uses two switches and an IC to electronically control the audio output from an amplifier. Digital
This is an interesting project where the intensity of a lamp can be controlled by touch. Most lamps only have an on/off switch. They don’t have any regulators to increase or decrease the intensity of lighting. Having such a built-in feature is available for some expensive lamps. But the same can be achieved without emptying
This is a simple electronic project suitable for everyone. This project is about making a LED bar graph thermometer using two ICs, one for the sensor. What is a bar graph thermometer? A bar graph thermometer is one that shows temperature reading using an array of LEDs instead of a digital numerical output. Here this
A simple electronic combination lock is designed using IC LS 7220. This circuit can be used to activate a relay for controlling (ON & OFF) any device when a preset combination of 4 digits are pressed. The circuit can be operated from 5V to 12V. The LS7220 IC is a MOS digital lock IC that
A simple “tone generator” is a cool circuit that everyone must build in their electronics learning process. We’ve designed this tone generator circuit using 8021 IC, two transistors (BC548 or C8050), a small speaker and some associated components. As you see, components are minimal and you don’t need to spend more than a small amount
A digital stopwatch is an evergreen project, it can be done at any time no matter how our advanced our world’s technology is because nothing else can replace a stopwatch. And also this is a suitable hobby project for newbies. This is a simple p[roject which doesn’t require much expertise or components. The list of
In this project, let’s learn how to make an Inverter – a Simple 40 watts inverter circuit using minimal components. An inverter circuit is often used in DC to AC applications and is necessary for many electronics applications. The heart of this circuit is a digital IC CD4047 – which is a very popular component.
In this project, let’s learn how to make a Simple Proximity Detector or Sensor circuit using minimal components. A proximity detector is a fun project with lots of interesting applications to be built with. You can make very useful applications like a burglar alarm, a visitor counter, a proximity-based switching application, etc. This is a
In this project, let’s learn how to make a simple “Long-range FM transmitter” at a low cost using minimal components. As you can see in the diagram, the circuit is simple, easy to build and test. Let’s begin to build our long-range FM transmitter. How To Build a Long Range FMÂ Transmitter The use of transmitters
