I'm trying to do a simple 555 circuit and can't seem to get a square
wave on my output.
I'm using the circuit found at http://home.cogeco.ca/~rpaisley4/LM555.html#3
and am using 1.5K for R1, 5K for R2 and a 47 uF for C (although my
radio shack meter says its a 59 uF).
The output I'm trying to read on a 20 MHz oscope shows a slight ripple
in the millivolt range, but no square wave.
I know its an open collector output, so I put a 10K pullup resistor to
the 5 volt rail, but still no square wave.
Its possible that I'm not using my o-scope correctly because I just
got it on ebay. It does seem to read correctly for the 5 volt supply
as well as another 24 volt supply, but thats just DC volts, no wave
form.
Other points to note,
* The 1.5K on R1 has a 15 turn pot
* The 5 K is actually 2 10K's in parallel
* This chip is a 556 (dual timer) but I have made sure to remap the
pinouts.
* I'm running Vcc of 5 volts.
Any suggestions would be greatly appreciated.
Thanks.
wave on my output.
I'm using the circuit found at http://home.cogeco.ca/~rpaisley4/LM555.html#3
and am using 1.5K for R1, 5K for R2 and a 47 uF for C (although my
radio shack meter says its a 59 uF).
The output I'm trying to read on a 20 MHz oscope shows a slight ripple
in the millivolt range, but no square wave.
I know its an open collector output, so I put a 10K pullup resistor to
the 5 volt rail, but still no square wave.
Its possible that I'm not using my o-scope correctly because I just
got it on ebay. It does seem to read correctly for the 5 volt supply
as well as another 24 volt supply, but thats just DC volts, no wave
form.
Other points to note,
* The 1.5K on R1 has a 15 turn pot
* The 5 K is actually 2 10K's in parallel
* This chip is a 556 (dual timer) but I have made sure to remap the
pinouts.
* I'm running Vcc of 5 volts.
Any suggestions would be greatly appreciated.
Thanks.