Discharge resistors take on stored energies. They discharge inductances, capacities or batteries. In the latter case, they are used to find out how much capacity is left in a previously fully loaded accumulator battery. To this effect, the battery is discharged with a defined current that is adjusted with the discharge resistance. The ratio of discharge current and the measured discharge time indicate the capacity of the battery in ampere-hours. Large-capacity condensers have to be discharged within one minute after shut-off such that the available residual voltage is below 65 V. To this effect, a discharge resistor is connected in parallel. Important inductances also have to be discharged via a resistor connected in parallel to them to prevent inadmissibly high shut-off voltages. The resistor converts the energy stored in the magnetic field of the inductance to heat.

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