Have a simple sawtooth generator, that works ok, but the variable resistor(RV1) does nothing.
As well, can I vary the frequency of the output?
Thanks in advance

 

The LTspice sim works fine (below):
Output shown for a pot wiper setting of 0% (green trace), 50% (yellow trace), and 100% (red trace).
Note that the output cannot drive any significant load, so an output buffer would be needed for that.

 

Hi Kim.
This is another option.
Shows Pot at 10% and 90%.

E

Update: Image #2.
By adding R1 [ which could be a variable resistor] it is possible to adjust On/Off periods of the output pulse.

 

the variable resistor(RV1) does nothing.

Then you have something wired incorrectly, or a broken pot.

 

Hi Kim.
This is another option.
Shows Pot at 10% and 90%.

E

Update: Image #2.
By adding R1 [ which could be a variable resistor] it is possible to adjust On/Off periods of the output pulse.

View attachment 318255View attachment 318258

Thank you very much for your valuable help. I will be rebuilding another according to your updated schematics. Does it matter if I am using a 7555 for lower running operation??

 

The LTspice sim works fine (below):
Output shown for a pot wiper setting of 0% (green trace), 50% (yellow trace), and 100% (red trace).
Note that the output cannot drive any significant load, so an output buffer would be needed for that.

View attachment 318240

Thank you very much for your valuable help. I will be rebuilding another according to your updated schematics. Does it matter if I am using a 7555 for lower running operation??

 

Does it matter if I am using a 7555 for lower running operation??

No, that should work okay in your circuit.
That is a CMOS device with lower input bias currents, so higher values of resistors can be used, if needed.

 

Thank you, I truly appreciate it