Sunday, January 17, 2016

More current from 78xx regulators

Yesterday I needed a little more current from a LM7805 series regulator. This was because I had no heat sink available and it was going in thermal shutdown without giving me time to test the application (more on this application on a future post).

I looked for a 2n3055 or 2n2955 to extend the output current, had none! Bad luck! (that I could find anyhow)

Thinking a little bit, I tough in paralleling, found some circuits which didn't appeal to me, so resorted to the datasheet to find the best way.
By the way, used this document for reference:

Here' the resulting circuit (with my adaptation):

I didn't placed the caps, was just a quick test. The resulting quick deployment:

Diodes were 1N4007 but any of one from the 4000 series will do.
It worked fine, anyhow I should place 3 instead of 2 since their still getting hot to fast (heath sink's are on my to do shopping list!..), well it gave me time to test and that is enough.

Another possibility if a 2N3055 or 2N2955 is available (circuit is for 2955):

Have a nice day!

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