Problem with 555 timer

Thread Starter

David_Baratheon

Joined Feb 10, 2012
285
It's ok, I'm absollutely stumped. Can't for the life of me work out whats wrong with it. Oh well, only has to be in tomorrow. Not to worry
 

Thread Starter

David_Baratheon

Joined Feb 10, 2012
285
If you want to test the 555 itself, the hysteretic oscillator would do that just fine.
Ok but does that involved setting up a whole new circuit? Unfortunately this is for a project to be in tomorrow so I dont think i can spend time making additional circuits. ive replaced the 555timer and it still didnt work
 

Audioguru

Joined Dec 20, 2007
11,248
I think you have destroyed the 555 by shorting its output by trying to measure its shorted output current to ground and having it trying to drive the LED without a current-limiting resistor. Don't doo dat!

I also think that your little 9V battery is dead. Measure the 9V battery and the regulator output voltages with the circuit running.

To measure the current in the LED then you must connect the current meter IN SERIES with the LED, and not simply short the output.
 
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