Hi
Just a quick question - Why is it that when you trigger a 555 timer the output goes high immediatley for a set period of time as determioned by the RC network?
Thanks.

 

See: http://www.uoguelph.ca/~antoon/gadgets/555/555.html

Or Google: 555 circuits

Ken

 

Thanks, Ill check them out, do you know if Id be right in saying that the reason the output state changes once triggered is because the capacitor is discharging through the resistor for a period of time?

 

Are you using the 555 in an monostable mode? if you could provide us with the circuit.. that would be great

 

Hi
Just a quick question - Why is it that when you trigger a 555 timer the output goes high immediatley for a set period of time as determioned by the RC network?
Thanks.

Because when you trigger the 555 it sets its output high and waits for the voltage across the capacitor to be the 2/3 of the supply voltage. It knows when the capacitor attains this voltage by using an internal comparator to monitor the voltage across the capacitor compared to the 2/3 of Vcc. When the capacitor reaches this voltage the 555 resets its output to a low state (it was high).