So I designed a circuit with these two main parts:
1. The timer, powered by 12V DC consists of a 555 timer circuit enhanced with Op-Amp regulator circuit. This part is connected to irg4ph40upbf IGBT.
2. Voltage regulator, powered by 24V DC.

I connected those two, and I already got the results that I wanted. The thing is, these two part is supposed to be connected to a pulse transformer that has working frequency at 50 kHz. the circuit I created only has max freq of 40 kHz. How can I amplify this freq to my desired freq?

  • 2
    \$\begingroup\$ Reduce the value of your 555 timing capacitor by 25%. \$\endgroup\$ Mar 26, 2016 at 4:55
  • 4
    \$\begingroup\$ You cannot "amplify" a frequency...!! Wrong term used. \$\endgroup\$ Mar 26, 2016 at 5:05
  • \$\begingroup\$ What prevents the pulse transformer working at 40 kHz? That's not so very far below its nominal working freq? \$\endgroup\$
    – user16324
    Mar 26, 2016 at 12:16

1 Answer 1


There are three ways.

  1. Reduce the size of the timing capacitor
  2. Reduce the resistance(s) of the two timing resistors slightly
  3. Bring the "control" voltage on pin 5 down a little.

I'd go with @WhatRoughBeast's comment above. Reduce the cap.


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