The circuit shown here is a one-box driver for scratch drive actuator. The printed-circuit-boad is mounted on top of a power supply, which has been removed from a PC. Voltages of +5v and +/-11v are used for operation. Either 5v or 11v is dc-dc converted by EMCO Q01-5 up to 100v or 220v, respectively. This voltage is switched by using bipolar transistors of large Vceo (=600v). A relaxation oscillator of an op-amp is built on the board to generate a switching signal to the transistors (see related pages: Penny Driver, 2D scanner driver).