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lm7805

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A heatsink is a piece of aluminum that conducts heat very well with many fins so it has high surface area. Steel washers do not perform like a heatsink because steel is a poor conductor of heat and the surface area is low.
We use a thin layer of "thermal compound" that conducts heat well (not super glue) beteen the regulator and the heatsink to fill in the microscopic dents in the surfaces for good heat conduction. Then they are bolted together.

A 7805 has a metal tab that is bolted to a heatsink. A 78L05 is small without a metal tab. Gluing it to a piece of metal does not help cool it much.
 
A heatsink is a piece of aluminum that conducts heat very well with many fins so it has high surface area. Steel washers do not perform like a heatsink because steel is a poor conductor of heat and the surface area is low.
We use a thin layer of "thermal compound" that conducts heat well (not super glue) beteen the regulator and the heatsink to fill in the microscopic dents in the surfaces for good heat conduction. Then they are bolted together.
Thanks ag
A 7805 has a metal tab that is bolted to a heatsink. A 78L05 is small without a metal tab. Gluing it to a piece of metal does not help cool it much.
Thanks ag

Yes a 7805 is a 1 A device and a 78L05 is a 100mA device . The 78L05 is all plastic so glueing it to the plastic case of a dead 7805 (on the plastic side ) seemed like it would work and in fact it does work well for any who read this. There is a metal tab encapsulated in the 7805 which would then do the cooling admirably as was intended . There is just more plastic too.

Any similar device that has died would do . I am not aware of an adhesive thermal transfer grease.

My interest in the bolt was that it says "washers"
I take that to mean many rather than one and of what material I wondered .Also I wondered if there was a way to bolt it to the chassis but keep it insulated. But if the original poster id not around much it matters little
 
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The chip inside a big 5V regulator gets hot. Inside a 7805 the chip is bonded directly to the metal tab for good heat conduction.
The chip inside a little 78L05 has plastic around it that does not conduct heat well to an outside piece of metal.

We bolt voltage regulators, transistors and Mosfets to a heatsink sometimes with an insulator in between. The insulator is mica or a new thermal material that is thin so it conducts heat very well.
 
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