Capacitor discharge pens are used to quickly discharge the stored charge in high-voltage capacitors or AC capacitors in switching power supplies during product repair. This prevents residual shock during repair and protects the operator and the product from damage. The capacitor discharge pen uses a constant current source circuit for rapid discharge. The red and black test leads are used without polarity distinction. Simply place the test leads directly onto the capacitor to be discharged. Discharge occurs without and features an LED indicator. When the LED turns on, the capacitor still has charge, while when it turns off, it's almost discharged., Manufacturer: Littimoon