IC 555 Timer Circuits Hobby Projects Astable Monostable Bistable Capacitor Resistor IC 556

Rain Alarm using 555 Timer - PCB

Rain Alarm using 555 Timer

Here is a simple and interesting hobby circuit that can be made using the popular 555 timer IC. As you might already know, a 555 Timer can be easily wired as Astable, Monostable or Bistable multivibrator. This circuit can be used as rain sensor, water overflow sensor or as a water level sensor. This circuit make use the principle that normal water can conduct some amount of electricity (PURE water is not a good conductor of electricity but water seen [...]

Simple Electronic Piano using 555 Timer

A simple electronic toy piano can be easily constructed using the popular 555 timer IC. 555 Timer can be easily wired as Astable, Monostable or Bistable multivibrator. We all know that Sound is a Mechanical Wave as it is produced by to and fro movement of particles of the medium. Displacement of particles are in the same direction as propagation of sound waves, so sound is a Longitudinal Wave. The to and fro motion of particles in the medium creates [...]

555 Timer

Bistable Multivibrator using 555 Timer

As the name indicates, a bistable multivibrator has 2 stable states. It can be switched from one state to another by providing an external trigger. It can be used for storing a binary digit (bit) as it has 2 stable states (0 or 1). So it is commonly used in digital circuits, where it is named as Flip Flop or Latches. A bistable multivibrator can be easily constructed using the most popular and low cost 555 Timer IC. Circuit Diagram - 555 [...]

TSOP17XX Pin Out

IR Transmitter and Receiver using 555 Timer and TSOP1738

IR Transmitter and Receiver pair can be easily made using 555 Timer, IR LED and TSOP1738 IR Receiver. This can be used for remote controls, burglar alarms etc. TSOP1738 is a very commonly used IR receiver for PCM remote control systems. It has only 3 pins, Vcc, GND and Output. It can be powered using a 5V power supply and its active low output can be directly connected to a microcontroller or microprocessor. It has high immunity against ambient [...]

Output - FM Generation using 555 Timer

FM Generation using 555 Timer

In communication systems, Frequency Modulation (FM) is the process in which information (message signal) is transmitted over a carrier wave by varying its instantaneous frequency. The difference between instantaneous frequency and central frequency of the carrier will be directly proportional to the instantaneous value of the amplitude of message signal. 555 Timer wired in Astable Mode can be used for generating Frequency Modulated (FM) waves. Please read the article Astable Multivibrator using 555 Timer for more details about the circuit. In astable multivibrator we [...]

Dancing Light using 555 Timer

A dancing light can be easily constructed using a 555 timer wired in astable mode. Please read the article Astable Multivibrator using 555 Timer before continuing. This circuit blinks two LEDs alternatively with some delay and it can be easily modified to include more LEDs or for controlling incandescent lamps. Time period of oscillation is determined by RC time constant of the circuit. Circuit Diagram 1st and 8th pins of 555 timer are used to provide power, Vcc and GND respectively. 4th is the Reset [...]

555 Timer

Monostable Multivibrator using 555 Timer

Monostable Multivibrator is also known as One Short Multivibrator. As its name indicates it has one stable state and it switches to unstable state for a predetermined time period T when it is triggered. The time period T is determined by the RC time constant in the circuit. Monostable mode of 555 Timer is commonly used for generating Pulse Width Modulated (PWM) waves. Circuit Diagram This is the circuit diagram of 555 Timer wired in Monostable mode. 8th pin and 1st pin [...]

555 Timer

Generating PWM Using 555 Timer IC

In applications like Motor Speed Control, LED Brightness Control we may want to vary voltage given to it. Most often we use a variable resistor for that. The main problem with this control is the power dissipation across the variable resistor. This problem can be avoided by using Pulse Width Modulation (PWM). In this method the average voltage delivered to the load is controlled by varying the duty cycle of the rectangular wave.  Here I'm going to discuss one of the simple technique to [...]