Author Topic: one or morfe heatsinks for power transistord of an analog symmetric PSU  (Read 612 times)

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Offline gibrancurtissTopic starter

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Hello guys.

I have a little analog symmetric PSU with -12V , +12V and +5V with linear regulators and I have to add a heatsink for the transistors. (TIP2955, TIP31, TIP3055)

My questions :
-may I add ONE heatsink for all transistors (even with regulators for positive and negative rails) ?
-if the transistors back could not share the same heatsink (avoid shorting) , is really save adding a mica or silicon pad to isolate their electrical conductivity ?
-where in the datasheet I can have the information what is the "leg" connected to the plate on transistor“s back?

Thank you !!!

« Last Edit: December 12, 2019, 11:22:57 am by gibrancurtiss »
 

Offline David Hess

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Re: one or morfe heatsinks for power transistord of an analog symmetric PSU
« Reply #1 on: December 12, 2019, 12:23:25 pm »
-may I add ONE heatsink for all transistors (even with regulators for positive and negative rails) ?

-if the transistors back could not share the same heatsink (avoid shorting) , is really save adding a mica or silicon pad to isolate their electrical conductivity ?

Yes, that is very important if the metal tabs are not at the same potential which will usually be the case.

Quote
-where in the datasheet I can have the information what is the "leg" connected to the plate on transistor“s back?

The pinout diagram should indicate it however for TO-220 and similar packages, it is always the center lead as far as I know.
 


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