boom3 Posted March 20, 2020 Share Posted March 20, 2020 On 3/18/2020 at 8:31 PM, Edgar said: Someone told me a long time ago that more heat is shed by the resistor leads than by the resistor body. If true, then the one longer lead on a stand-up resistor mount makes sense. Since the leads are metal and the body is ceramic or metal coated with enamel, that also makes sense. I would be surprised though if any low-level, signal-path resistors get appreciably warm, that suggests that they are undersized for the current. A very long time ago, I watched one of my profs open up a Tektronix o-scope, one of those the size of a studio TV camera. The signal-level components were almost all mounted on long ceramic pans with lead pads on either side. Makes for a more complicated wiring harness, but it looks very neat and easy to troubleshoot. Being used to the under chassis "rats nest" typical radio & TV construction, I was in awe. Some British gear did/does this as well. Quote Link to comment Share on other sites More sharing options...
glens Posted March 20, 2020 Share Posted March 20, 2020 On 3/18/2020 at 9:31 PM, Edgar said: Someone told me a long time ago that more heat is shed by the resistor leads than by the resistor body. If true, then the one longer lead on a stand-up resistor mount makes sense. If true, yes. But I highly doubt it's true. Surely a stand-up resistor is some combination of layout tidiness and better body dissipation via air all around it. An IR image would certainly settle the question. Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted March 22, 2020 Share Posted March 22, 2020 On 3/18/2020 at 8:50 PM, boom3 said: Stand up axial resistors? Have not seen those since 6-transistor pocket radios of the 60s. I'd think they would be more fragile than having the axials just lay on the board with the lads going to the pads. Not when they are packed like sardines. There's nowhere for them to fall. The height of the plastic case was determined by the relay, so it made sense to pack them on 0.1" center. with a 0.1" lead span. Remember, this is before surface mount became prevalent in the 90's. Quote Link to comment Share on other sites More sharing options...
glens Posted March 23, 2020 Share Posted March 23, 2020 Didn't it wind up getting potted anyway? Quote Link to comment Share on other sites More sharing options...
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