Ah yes, the 78xx series of linear voltage regulators.? If you consider the input/output voltage differential, there's quite a bit of power to sink (heat). Some have "staged" with additional voltage regulators in series in order to distribute the heat dissipation. eg. a 7809 or 7809 feeding the 7805.? Just be mindful of the minimum dropout voltage.
73 de Mike
On Wednesday, November 11, 2020, 01:57:42 a.m. EST, Bob Lunsford via groups.io <nocrud222@...> wrote:
An old axiom from a friend who worked designing power supply transformers and filter chokes is that if you cannot hold your fingers to the transformer and choke for a count of "thousand-one, thousand-two, thousand-three" without screaming, you used too much iron in the transformer/choke. I wonder if this is also an axiom when the use of heat sinks/radiators... For my radios/devices, I prefer to run them a bit cooler. I cannot see the radio/apparatus getting hot or even a component in it. "Getting away with it" when going hot for a device or element in one of my radios or devices is not the way to live when eventually heat, or even vibration, can eventually come to be a problem, eventually, and can be avoided merely by eliminating such sources of potential problem as time progresses.
Much of this us on the edge of possibilities/probabilities but often the theoretical is located at the portal of what eventually happens.
Bob ¡ª KK5R
On Tuesday, November 10, 2020, 10:49:10 PM EST, George <du9gt@...> wrote:
Greetings Kit Builders and Home Breweres!
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Just hav recently gotten my uBITx V6.
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It seems to work as advertised with these two anomalies:
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The 7805 Regulator on the Radrino display board unit is so hot I can not hold my fingers on the heatsink without great discomfort.
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Question: Is this normal?
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I notice some slight FMing in received signals and when I got ready to put some extra filter caps on the unit I noticed the heating on the 7805.
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Question:? Has anyone else noticed a slight FMing on receive, or does my unit have a problem (or problems)?
VE3MIC