Explaining How 555 Circuit works

[maherelharake]

Homework Statement

The problem is the attachment.

Homework Equations

The Attempt at a Solution

I am not sure what the appropriate answer is. Any suggestions?

 

[gneill]

I'm not sure what your appropriate attempt at a solution is

 

[maherelharake]

Haha yeah sorry it seems as if I didn't even think about it.

Well I know that 555's have properties such as:

low trigger input leads to high output
high trigger input leads to low output
it outputs a square wave
if the trigger isn't a max/min then there is no output

Not sure if these ideas are leading me up the correct path.

 

[gneill]

You need to figure out what the state of the 555 would be (that is, the output) if there were no input signal. Then what happens when a negative going input edge occurs (say just one negative going pulse). The internal block diagram for the 555 might help.

What will be the result of repeated input pulses? What's the transistor across the timing capacitor going to do?

 

[maherelharake]

Well based off my previous statements, would no input signal lead to a high output?
I don't know what would happen if an input edge occurs.
Wouldn't repeated input pulses just give repeated outputs?
I also don't know what the transistor would do


I'm not that great at this stuff

 

[gneill]

Do a google search on "555 missing pulse". You should turn up a circuit operation description. But you should really try to understand the block diagram of the 555 so that the operation is clear. The 555 is composed of some pretty simple functions that are just wired together in a clever way, and allow the 555 to behave in some very useful ways with just small changes in external wiring.