Bias and degaussing oscillation circuit of monophonic recorder

Shown is the bias magnetization and degaussing oscillation circuit of the tape recorder , which is mainly composed of transistor VT1 and an oscillation transformer. The primary winding of the oscillation transformer T and C1 form a resonant circuit. The resonant circuit is connected between the base and collector of transistor VTI and serves as a load for the collector of vri. C2 is the coupling capacitor. &, C4 constitutes a filter circuit, and the power supply +B voltage is added to the primary center tap of the transformer through R4 to provide DC bias to the base of the transistor VT1 through the winding.     The secondary output of the oscillation transformer oscillates the signal. Provides bias magnetic signals for the recording heads and provides silencing signals for the silencing heads. Selecting the value of C6 can change the size of the recording bias. to achieve the optimal magnetic bias amplitude.