Hi there, https://http://www.keil.com/mcb2140/mcb2140-schematics.pdf Does anybody know the reason and purpose for placing diodes D3 and D4 between the BJTs and ground? The schematic can be found at the url above. My electronics is rather poor so thanks guys for explaining it to me :) Cheers, Dexton
"the purpose of the diode is to protect the transistors T1/T2 and not the LPC2106?" Directly - yes; but indirectly they also protect the LPC2106. You'd have to think carefully to ensure that there are no failure modes whereby the transistor(s) would let -12V reach the processor...
Thanks guys! That really helped :) Cheers, Dexton