Abstract: Disclosed is a horizontal oscillation circuit for a monitor performing a stable oscillation even at the start input such as a power input or a mode change. The horizontal oscillation circuit for a monitor includes an operation voltage delaying part for delaying a time period for an operating voltage to reach a voltage level and for outputting a delayed operating voltage, and a horizontal oscillator for inputting the voltage corresponding to the operating mode, the horizontal synchronizing signal and the delayed operating voltage and for outputting a stable oscillation voltage corrresponding to the operating mode. With an output of a stable oscillation voltage from the horizontal oscillation circuit, the horizontal output circuit of a monitor can be protected from being damaged by heat and a stable display can be obtained even at the start input such as a power input or a mode change.

Abstract: A transistor protection circuit of a monitor for protecting a transistor from a high voltage liable to instantaneously occur during a power on/off or mode conversion includes a driving transformer for generating a high voltage driving signal according to a horizontal oscillating signal, a transistor which switches according the high voltage driving signal received into a base thereof and having an emitter being grounded, a flyback transformer connected to a collector of the transistor for generating a high voltage, and a high voltage cutoff unit connected between the base and collector of the transistor. Thus, the high voltage of the flyback transformer supplied to the collector of the transistor is bypassed to the high voltage cutoff unit when an abnormal high voltage instantaneously occurs to thereby protect the transistor.