Monostable acting screwy!

[2camjohn]

I havent used a 555 monostable since Grammar School but now I am trying to use one for switch debounce.

The problem is the pulse remains on as long as you hold the switch down, what i want is the pulse to be independant to the switch.

What kind of problems are associate with this kind of circuit? (I have already addressed decoupling)

 

[TillEulenspiegel]

Can you supply a schematic? 555's are pretty mundane tech, problly a wireing prob.
This is a debounce that is decoupled to not retrigger until the switch is opened.

 

[Screech]

Don't know what debouce is, but i use this circuit.
The left part is the trigger.
It doesn't mater how long you hold it down.

 

[Screech]

SORRY
should look like:

 

[ljcox]

Here is a simple bounce suppressor

The IC is a Hex Schmitt Trigger such as the 74C14, 40106, etc

 

[2camjohn]

Thanks LJCox, that seems nice and small.

If i wanted to vary the amount of bounce suppression what would I vary? The 1meg resistor?

 

[ljcox]

Thanks LJCox, that seems nice and small.

If i wanted to vary the amount of bounce suppression what would I vary? The 1meg resistor?

You can change either the resistor or the capacitor. But the resistor needs to be at least 100k to make it much greater than the 10k. Otherwise the timing will be assymetrical.

Be sure to connect all unused inputs of the IC to gnd.

Len