TV receiver with video recorder - has control circuit for changing transistor for either collector or base operation

摘要

A transistor(9) has a control circuit comprising a diode(12) and a resistor(11) connected in series between the base of the transistor and ground. During recording, a switching circuit(8) feeds video signals from the receiver (1) via a recording amplifier(6) to the base of the transistor and applies zero voltage to the junction of the diode and resistor to close the diode. Signals are fed from the emitter to the recorder(3). During playback, the switching circuit(8) connects the collector of the transistor to the input of the receiver via a playback amplifier(7) and applies +12 V to the junction of the diode and resistor to open the diode, grounding the base of the transistor. The signals from the recorder control the emitter of the transistor, and signals from the collector are fed to the receiver via the playback amplifier.