Planer motor main circuit and control circuit

The circuit of the woodworking hand planer safety device is divided into two parts: the detection circuit composed of quartz crystal, etc., and the main circuit and control circuit
of the planer motor, which consists of the quartz crystal HTD and the transistor VTi inter-electrode capacitance to form an oscillation element, with an oscillation frequency of 3MHz. When the hand approaches the danger zone of the tool axis, the oscillation frequency suddenly changes, the output signal of the transistor VTi suddenly decreases, VT2, VTa, and VT4 are cut off, the relay KAI is released, causing the contactor KMi to be released, and the motor brakes quickly. After parking, press the start button SBi again, and the planer will resume normal operation.     The inductor L is made of 0.15mm diameter sheathed wire wound on a high-frequency magnet with 133 turns.