MFD

[UltraLRL]

Are you Going to change the 8038 frequency by changing the capacitors?? No Way!!

Timing Capacitor Only determine the frequency range!!

USE A POT TO CHANGE THE FREQUENCY!

take a look at this simple 8038 generator:


The Basic characteristics of the circuit with a few components. By have VR1-potentiometer, R1-resistors and C1-capacitors are determined frequency output. Which has formula to calculate the frequency output as follows.

The Frequency output (f)
= 0.15/(VR1+R1)C1


Changing Frequency by turning the VR1 pot!



Another 8038 Generator:



The frequency of the output wave form can be adjusted using R7 .It must be a 100K Log POT.



Another One:



The IC contains an internal square wave oscillator, the frequency of which is controlled by timing capacitors C1 - C4 and the 10k potentiometer!