Quote:
Originally Posted by kalee20
I've never found that! For starters, Vbe is temperature dependent, so as the thing gets hotter, Vbe falls and you'd think it was passing less current.
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Actually you can do it (across a B-E junction or a rectifier junction as a current sensing element)see attached, one of my designs for a current sensor for a dynamo regulator (detecting the current by the voltage drop across a 180NQ035 power rectifier). One advantage of it is that you don't waste heat in a current sensing resistor. But it requires a thermally bonded diode (as indicated by the orange line in the diagram) to neutralize the temperature dependence you pointed out.