Produce high frequency square wave


Joined Sep 24, 2015
That test circuit only tests that the comparator is working. You won't see it blinking. But it's acting like a "Sink" for the LED, that is, it's grounding the LED to turn it on.


Joined Jan 23, 2018
From my reference manual it seems that the LM319 does not need a negative supply, but that the Vee pin can be tied to the positive supply common. As the Vee- pin is the reference for the inputs that may be the problem. So both "Gnd" pins, along with the Vee, need to tie to the V+ supply common (negative) side. My manual shows that, and claims that it can work down to +5 volts supply.

Thread Starter


Joined Sep 28, 2021
View attachment 254944
This (above) is the circuit I and others used. It is similar but this one uses and LC tank (C1 and Lx) connected to the non-inverting input of the LM319.

The LM319 is good for 36 volts so ±10 volts should be fine. If you use a split supply you will not need the resistor from (in the schematic above) +5V to the + input.
Hi sir, Merry Christmas :)
I have bought the LM 319N actually and I tested it but does not really work and I have asked it in another forum here


Joined Dec 24, 2013
Hi, I have tried your suggestion and all connections are secured with all resistance values being measured using multimeter and its correct. I am still not getting any good square wave output. Feel dissapointed :)
What do you get from output? How do you test it?