555 Timer Basics Tutorial, Pin Diagram

555 Timers can be used by Electronics Beginners to start off with developing assembled kits to sell online.

It is a highly stable integrated circuit capable of working as an accurate time delay generator and as a free running multivibrator.

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The 555 timer IC was first introduced in early 70's by the Signetics Corporation as the SE555/NE555 and was called "The IC Time Machine".

555 Timer Pins

Pin1-Ground:

The ground or common pin is the most-negative supply potential of the device.

Pin2-Trigger:

It can be done by momentarily ground the terminal.

Pin 3-Output:

The output voltage available at this pin is approximately equal to the Vcc

applied to pin 8 reducing 1.7V.

Pin 4-Reset:

Reset the latch and return the output to a Off or low state

Pin 5-Control:

Direct access to the 2/3 V+  voltage-divider point. Indirect access to

 lower comparator.

Pin 6 -Threshold:

one input to the upper comparator. Makes Output low

Pin 7-Discharge:

Connected to the open collector of a npn transistor.

Pin 8-V+:

Positive supply voltage terminal of the 555 timer IC

Features of 555 Timer

1.Timing is from microseconds through hours.

2.O/p is Compatible with CMOS,DTL and TTL

3.High Temperature Stability

4.Duty Cycle is Adjustable

5.Monostable and astable operations

Specifications of 555 Timer

Voltage VCC	4.5 to 15 V
Current (VCC = +5 V)	3 to 6 mA
Maximum O/P Current	200 mA
Power dissipation	600 mW

The 555 Timer is available in 8 pin and 14 pin

dual in line packages. The Device comprises of two comparators, two control transistors, a flip flop and a buffer output stage. Comparators is an op-amp that compares an input voltage and indicates whether the input is higher or lower than reference voltage

We can use a 555 Timer for accurate timings or precision timings, time delay generation and pulse generation.     

555 Timer Monostable Operation

The Circuit triggers on a negative going input signal when level reaches

one third of Vcc.

555 Timer Astable Operation

It will trigger by itself and run as a multi-vibrator.

555 Timer Bistable Operation

It can operate from many different supply voltages uses small amount of power and requires no external components .