A novel spotlight where the position of image formation does not change even when the zoom adjustment is made after focus adjustment, so that focus adjustment and zoom adjustment can be facilitated. The first automatic level control circuit has a first predetermined attack time and a first predetermined release time longer than the first predetermined attack time. The circuit component 4A for realizing the NAS function, liable to become hot, is provided with a heat sink 5. After the cartridge has been securely received by the interface mechanism, the connection sequence is initiated. The output stage may include additional circuitry to ensure that parasitic capacitances associated with the gates of the p-type field effect transistor and the n-type field effect transistors are discharged at appropriate times such that power consumption is reduced and high-speed operation is enhanced. The voltage source converter includes at least one phase element including a plurality of semiconductor switches to interconnect a DC voltage and an AC voltage.