Should TO-39 transistors be mounted flush to the PCB, or should they be mounted slightly above the PCB? If so, why?
Mounting flush can give better heat dispersal, particularly if the PCB tracks are so designed to aid that. That said for normal low power usage I always use to mount them a little above.
You used to be able to get mounting pads (think spacers) for these and other old timer outlines.
You used to be able to get mounting pads (think spacers) for these and other old timer outlines.
My old Marantz amp has little spacers between the bottom of the transistor and the PCB. That made me wonder about spacing them above the board, maybe 0.100" or so above the board.
I'm putting together a couple Leach Amp boards that has 2N3440 and 2N5416 transistors, look like they are predrivers for the driver transistors in the circuit.
I'm putting together a couple Leach Amp boards that has 2N3440 and 2N5416 transistors, look like they are predrivers for the driver transistors in the circuit.
All metal case transistors shouldn't be mounted directly flush to the PCB. They all need some space, 3-5 mm (or at least 0.100").
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In the TO-39 and the like heydays we were told to leave transistor leads as long as possible to avoid overheating during the soldering process. Yours' arent 2N1613 or 2N1711 with leads of about 2", are they?
Best regards!
Best regards!
Looks like you're talking about a Leach amp - if you flush-mount them - it's easier to "push" the heatsinks on top ... without folding its long legs ... but there's little room for heatsinks... And they are quite warm, but think you can do without a heatsinks...i have them so i use them.
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Ok, well, then cut the leads to ~½" before soldering.
I might have muddled TO-5 (short leads, collector lead protruding the metal case bottom) with TO-39 (long leads, case bottom of an isolating material).
Best regards!
I might have muddled TO-5 (short leads, collector lead protruding the metal case bottom) with TO-39 (long leads, case bottom of an isolating material).
Best regards!