LM358 VCO Circuit

Print Friendly, PDF & Email

This isn’t clear for beginners, but V/2 at pin 5 non-inverting input of amp 2 means you have to add another 2 x say, 10k resistors as a voltage divider to supply the correct voltage at pin 5 – NOT the full PSU voltage (5V) as I did at first – else it won’t work.

The pin 5 100k/51k resistors are the feedback, not the voltage dividers..duh!

With a 47uF cap at pins 1-2 I get the correct outputs: