What is 555 IC?

What is 555 IC?​

The 555 is an 8-pin chip that can be turned into lots of different things (building blocks). The circuit inside the 555 is just an amplifier with 2 inputs and an output.
The parts you add to the chip determine the final result (effect). In most cases you add a capacitor and resistor to produce a circuit known as a TIME
DELAY CIRCUIT and the chip has a detection-pin and an amplifier (also called a power amplifier) to produce an output.

It is not just a "timer," "delay" or "oscillator" but is capable of being converted into these and
maybe 100 other circuits. Just call it the "555"

The 555 HOW IT WORKS​

To understand how the 555 works, you need to know how to connect pins 2 and 6.

What you should know is as follows:​

Pins 2 and 6 should never be left disconnected because doing so will cause the 555's output to occasionally be LOW or HIGH
Due to their HIGH IMPEDANCE, pins 2 and 6 have the ability to detect static electricity and occasionally turn the 555 on or off.
Here are the 4 possibilities for pins 2 and 6:

The four options for pins 2 and 6 are as follows in the Table below:​

Pin 2 LOW	Pin 6 LOW	Pin 3 HIGH	Pin 2 controls the 555 IC. Pin 6 Has no effect
Pin 2 LOW	Pin 6 HIGH	Pin 3 HIGH	Pin 2 controls the 555. Pin 6 has NO effect.
Pin 2 HIGH	Pin 6 LOW	Pin 3 LOW	Pin 2 controls the 555.(the 555 does not turn on)
Pin 2 HIGH	Pin 6 High	Pin 3 LOW	Pin 2 controls the 555. (the 555 does not turn on)

Connect pin 2 and 6 together. Take both HIGH . . . .. Pin 3 LOW (toggle Mode)
Connect pin 2 and 6 together. Take both LOW . . . .. Pin 3 HIGH (toggle Mode

Toggle Mode is also called INVERTER MODE . . . The output is opposite to the input. The 555 takes 10mA ALL THE TIME . . . even when the output is LOW