I have a capacitor labeled 1 μF (micro Farad) and when I measure capacitance I get 1 μF but when I measure resistance the meter shows out of range on any dial setting except on 200 MΩ (mega Ohm) where it shows a constant value.
Is the capacitor good or bad?
Best Answer
A real-life capacitor can be modelled as an ideal capacitor of nominal value parallel with a resistor (\$R_p\$), and this all is in series with another resistor (\$R_s\$). \$R_s\$ is the equivalent series resistance (several ohms), something that comes from the fact that the pins of the capacitor have some resistivity.
simulate this circuit – Schematic created using CircuitLab
The parallel resistance, \$R_p\$, is ideally infinite, because in an ideal insulator has zero conductivity. As no real insulator is ideal, the parallel resistance that depicts leakage has some finite, but usually quite large value. When you measure the resistance of a capacitor, you will get a value of \$R_s+R_p\$, which is likely to be pretty large as well.
That said, and knowing you only got a value when measuring in the 200 M\$\Omega\$ limit, your capacitor seems alright.