I'm working on building a soft-latch power switch. Before I build the entire thing, I'd like to ensure that I can simply latch power on, without adding off functionality. I am wondering why the following circuit won't latch. If I press the switch, the LED lights up. But upon releasing the switch, the LED switches off.
I don't understand why the base of the bottom transistor doesn't 'see' the voltage at the emitter of the top transistor.
I am using ZTX457 NPN transistors. http://www.diodes.com/datasheets/ZTX457.pdf