Auto power off circuit of video cassette recorder

摘要

this research is of the VCR off in order to let the band play, automatically cut off the power supply to the video cassette recorder of automatic power off circuit on a head (10), in the play to increase the regenerative amplifier (30) and (31 high frequency) as the frequency of the high pass filter through to the station (50) and the frequency of the low pass filter (51) is through a color signal (c) of the trade of the circuit, the low pass filter (51) in the color (c). the voltage conversion f / v converter (60) and the letter. the selected color (c ') a signal voltage conversion f / v converter (61) in the two to be compared with the voltage is the same, the "low" signal does not match the output, if the output is a signal comparator (cp). the transistor base to connect to (Q).the collector of the power switch (70) to / from the command relay (RY) connected to the comparator (cp), the voltage is compared with VCR regeneration is completed, to judge the power switch (70), the unnecessary power consumption. can prevent.