Quote:
Originally Posted by OldTechFan96
I used my Avo8 to measure how much current the radio was drawing. To my surprise It was drawing 2A of current!
|
Ouch! The internal resistance of a standard PP9 is roughly 3R (so the battery behaves as if this is in series with a 9V voltage source - I recall this from somewhere in Horowitz and Hill...).
So a
fresh 9V battery can source an astonishing 3A, but only for a minute or so! It must have got pretty hot in seconds!
You'd have temporarily measured a voltage drop of 2A*3R=6V from circuit +ve to ground, so displaying just 3V, assuming this internal resistance.
Good thinking to work out what could produce such short-circuit conditions!
