Abstract: A flash control circuit for use with a system controller is disclosed. The circuit includes a booster unit for receiving a first voltage signal and for outputting a second voltage signal to a lamp. The booster unit boosts the first voltage signal and then charges the boosted first voltage signal. Also included is a voltage sensor for sensing the voltage of the second voltage signal and for transmitting a voltage indication signal to the system controller. An oscillator outputs the first voltage signal according to an oscillation control signal from the system controller, and a triggering unit generates a trigger pulse according to a lighting control signal output from the system controller. The circuit further includes an accidental lighting prevention unit coupled to the triggering unit.

Abstract: A manual focusing circuit of a camera comprising a rotation ring having a plurality of projections, wherein the ring is manually rotated forward and rearward by a user. The manual focusing circuit further comprises a first sensing element, which is coupled to one of the projections of the rotation ring, for producing a first signal; a second sensing element, which is coupled to another of the projections of the rotation ring, for producing a second signal having a phase difference of 90 degrees against the first signal; a signal stabilizer, which is coupled to the second sensing element, for removing a noise from the second signal to produce a stabilized signal representing a rotation number of the rotation ring; and circuitry, which is coupled to the first sensing element and the signal stabilizer, for producing an output signal representing a rotation direction of the rotation ring based on the first signal and the stabilized signal.