DC power boost circuit b

The touch switch power supply circuit is shown in the figure. No external transistors are required on the small printed circuit board of the music block. The upper part of the figure is the "open" circuit.
When the "open" contact piece is touched, 1C1 is triggered . The positive half cycle of the music signal causes the switch tube VT1 to conduct, the relay KR pulls in, the contact krl
closes , and the positive power supply passes through Ri. VT1 provides bias current and the circuit is self-protecting. Contact kr2 is pressed at the same time to make the load work. The lower part is the "off" circuit.
When the "off" contact piece is touched, 1C2 is triggered , and VTZ is turned on when the sound bed signal is positive, causing the VT1 bias current to be bypassed and VT1 to be cut off. '
KR is released, the contact is disconnected, and the load stops working