Capacitor Safety Discharge Calculator
This tool is used for calculations involving the discharge of a capacitor through a fixed-value resistor. Given a capacitance value as well as beginning and end voltages, this calculator solves for either time or resistance, calculating the resulting initial power dissipation in the resistance and the total energy discharged to zero volts.
Many factors need to be considered when choosing a discharge resistor. Safety standards require the voltage across a capacitor to reach a safe voltage before a person is able to touch it. In the USA, standards such as UL, OSHA, NTA, ETL, MET, etc. will have the requirements available for the needs of your product.
Capacitor Value
µF
Initial Charge Voltage
V
Safety Threshold Voltage
V
Warning: Safety Thresold Voltage should not exceed Initial Charge Voltage.
Resistance Value
Ω
Safe Voltage Achieved by
=
s
Initial Power Across the Resistor
=
W
Time Constant
=
s
Energy Discharged to Zero Volts
=
J
Desired Discharge Time
s
Safe Voltage Achieved by
=
Ω
Initial Power Across the Resistor
=
W
Time Constant
=
s
Energy Discharged to Zero Volts
=
J

Recommended Products
TDK-Lambda Related Articles
CUS350MP-1000 Medical and Industrial Power Supplies
TDK-Lambda’s CUS350MP-1000 power supplies can provide 500 W with 1000 W peak for 1 s or 350 W with 800 W peak for 5 s, depending on the cooling method chosen.
Learn More
CUS350MP-1000 Medical and Industrial Power Supplies | Datasheet Preview
TDK-Lambda’s CUS350MP-1000 power supplies can provide 500 W with a 1,000 W peak for 1 second when external airflow is applied, or 350 W with peaks of 800 W for up to 5 seconds when convection cooled.
Learn More
DRB120 to DRB960 3-Phase DIN Rail Power Supplies
TDK-Lambda's DRB120 to DRB960 3-phase DIN rail power supplies are suitable for industrial machinery, communications equipment, and more.
Learn More
CUS250M Series 2” x 4” 250 W Power Supplies
TDK-Lambda’s CUS250M power supplies have a mechanical configuration enabling both convection and conduction cooling through the baseplate for silent cooling.
Learn More
TPS4000 Series 3-Phase 2040 W to 4080 W Industrial Power Supplies
TDK-Lambda's TPS4000 series 2040 W to 4080 W industrial power supplies operate from 400 VAC, 440 VAC, and 480 VAC Delta and Wye inputs.
Learn More