May 19, 2014

FCC Technician Exam Question Of The Day (T7D10)

Q) What is probably happening when an ohmmeter, connected across a circuit, initially indicates a low resistance and then shows increasing resistance with time?

A) The circuit contains a large capacitor

NJ2X Notes:
When a voltage is connected to a resistor and capacitor in series, the initial current is high as the battery transports charge from one plate of the capacitor to the other. The charging current approaches zero through time as the capacitor becomes charged.  Charging the capacitor stores energy.