Cap dump crkt from book not working, HELP!

[Carlos Galvis]

Hi all, i have benn trying to build the circuit on the intermediate book, but as i hook up the charge battery the voltage regulator 7812 burns up! i managed to find all the parts except for the H11d1, i found the hd11d2... i guess the question is, is this the reason my 7812 is burning? if so, whats a suitable replacement for the h11d1? thanks! heres the circuit diagram

[Retep]

No Worries, Mate!

Hey Carlos,

The H11D2 should be fine. The circuit doesn't specify the resistor values, so the easiest way to make it work is like most of the other circuits shown, where the collector of the H11D1 is connected back to the collector of the BD243C. That way you can forget about the 7812 voltage regulator. You may need to take the 330 ohm resistor out between the H11D1 and the base of the BD243C as well.

You can see the basic circuit run that way back on page 36 of the Intermediate Handbook.

Good luck,
Peter

[Carlos Galvis]

Hey Carlos,

The H11D2 should be fine. The circuit doesn't specify the resistor values, so the easiest way to make it work is like most of the other circuits shown, where the collector of the H11D1 is connected back to the collector of the BD243C. That way you can forget about the 7812 voltage regulator. You may need to take the 330 ohm resistor out between the H11D1 and the base of the BD243C as well.

You can see the basic circuit run that way back on page 36 of the Intermediate Handbook.

Good luck,
Peter

Hi retep, your post was most helpful, thank you very much, the circuit is up and running perfectly, time to get testing! here's the diagram of the modifications i made based on your suggestion, i haven't removed the 2k resistor between h1d2 and base of bd243c just to see how it will work, why do you say it should be removed? i shall try it...