On Tue, Jul 23, 2024 at 03:58 PM, Steve Ratzlaff wrote:
For a second thing, whoever came up with that circuit apparently knows nothing about bipolar transistors. You cannot simply parallel bipolar transistors unless you add separate series emitter resistors.
Hi Steve,
i think i remember the said circuit. It was together with a picture of the board layout. The bipolar transistors are not really in parallel. It's for the sake of the pcb-board layout CAD Software requirement. The pcb designer intended to be able to later choose between an SMD or a throug-hole bipolar transistor type. To achieve this , he had to put the SMD-type and the th-type in parallel in the schematic diagram, to get the two footprints identically connected on the pcb board. Many PCB-CAD software work this way.
?
regards
Fred
