A LM-555 Timer is a commonly used IC designed to produce a variety of output waveforms with the addition of an external RC network. The name 555 is derived from the fact that it has 3 resistors with values of 5Ω each. It is a highly stable device for generating accurate time delays or oscillation. Additional terminals are provided for triggering or resetting if desired. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor. For a stable operation as an oscillator, the free running frequency and duty cycle are accurately controlled with two external resistors and one capacitor. The circuit may be triggered and reset on falling waveforms, and the output circuit can source or sink up to 200 mA or drive TTL circuits.
A 555 Timer IC has 8 pins for different purposes, as listed down:-
1. Ground
2. Trigger
3. Output
4. Reset
5. Control
6. Threshold
7. Discharge
8. VCC
How to use
Timer IC – LM 555 – Pin Out
Tutorial – ( )
https://youtu.be/CvpP1PaQKo0
Common Applications
1. PWM (Pulse Width Modulation) & PPM (Pulse Position Modulation)
2. Duty Cycle Oscillator
3. To generate Pulse, Waveform, and square wave.
Some example projects that students can try out in the ATL Lab
1. Automatic Time Indicator for Telephone using IC 555 –
https://bestengineeringprojects.com/automatic-time-indicator-for-telephone/
2. Latching Touch Sensitive Alarm Circuit Using 555 Timer IC –
https://elonics.org/touch-sensor-alarm-using-555-timer-ic/
Safety Measures to follow
1. Use the product within the ratings specified for ambient operating temperature and ambient operating humidity for each model.
2. Separate the input devices, input wiring, and product as far as possible from sources of noise and power lines carrying noise.
Important Links
1. How does 555 Timer IC work (https://youtu.be/EGmreVQ-yNM)
