A discharge circuit, an image forming apparatus having the discharge circuit, and a power-supply unit are disclosed to minimize a standby power generated in a standby mode and improve a discharging speed of a capacitor charged with electricity by the AC po...

Pulse signal generating circuitry (120) generates a pulse signal (iii) for the primary side of a piezoelectric transformer (101). A voltage dependent upon the frequency of the pulse signal is output from the secondary side. The circuitry compares an output...