mobile phone headphone autput?

Thread Starter

Poor old sod

Joined Jul 25, 2017
want to connect headphone output to base/emitter of switching 300mw transistor whilst running sq wave gen app. to test e-speedo/wiring. hall effect trigger. how to avoid blowing things up? have 4.7k and 5.1k resitors, 9 ea. expect volt divider input with transistor pulse-shorting one. at low Hz.


Joined Jun 22, 2012
Line level output standard is 0.77V into a 600 ohms load, but most headphones are anything from 16 to 100 ohms, best solution is to measure it..