# Ic 555

#### vick5821

Joined Jan 27, 2012
54
Just to confirm my understanding about IC 555 .

When the output Q of the flip flop is high, then transistor is ON and the output is LOW ?
If the output Q of the flip flop is low, then the transistor is OFF and the output is HIGH?

So does that means the the output is follow the output of Q bar ?

Am I correct ?

I am still blur with the internal circuit of IC 555

#### Wendy

Joined Mar 24, 2008
23,396
I have written a set of tutorials on the suckers.

When Q is high, the output is high.

The 555 Projects

#### vick5821

Joined Jan 27, 2012
54
I have written a set of tutorials on the suckers.

When Q is high, the output is high.

The 555 Projects
Can you show me which internal block diagram you are referring to ? I thought after the flip flop there is an inverter logic(buffer) before the OUTPUT Pins? Like if Q= HIGH, so it will be inverted to become LOW in the OUTPUT pin ?

#### Wendy

Joined Mar 24, 2008
23,396
Can you show me which internal block diagram you are referring to ? I thought after the flip flop there is an inverter logic(buffer) before the OUTPUT Pins? Like if Q= HIGH, so it will be inverted to become LOW in the OUTPUT pin ?

555 Schmitt Trigger

#### vick5821

Joined Jan 27, 2012
54

555 Schmitt Trigger
LOL..I thought schmitt Trigger is another mode of 555 operationn ?

#### Wendy

Joined Mar 24, 2008
23,396
It is. But if you study the 555 you will find that core circuit is used in an amazing number of applications. A lot of electronics is built on previous knowledge.

The article I pointed to has the internal block diagram for a 555 laid out.

One of the things that makes the 555 special is its relatively large drive characteristics. Not too many parts can handle up to 200ma (0.2A) on the output.

Here are some other ideas you might find interesting over time.

LEDs, 555s, Flashers, and Light Chasers