Remote control toy car receiver circuit

The high-frequency signal sent from the transmitting end is received by the receiving antenna. The super-regenerative receiving circuit composed of Q1, L2, C2, C3, etc. L2 and C2 are parallel resonant circuits, which are used for frequency selection. C3 is a super-regenerative positive feedback capacitor. Adjusting L2 can change the receiving frequency. R1, R2, and C5 determine the extinction voltage of super-regeneration. The received signal is sent to the {14} pin of the decoding circuit RX-2 through R4 and C7 for amplification. The amplified signal is output from the {1} pin and sent to the {3} pin of the decoding signal output terminal through R8 for decoding. When the decoding circuit decodes the received signal, if it is a forward signal, the {11} pin outputs a high level, Q11 is turned on → Q12, Q13 are turned on respectively, +4.5V and so on are passed through Q12 → MA → MB → Q13 → ground, the motor rotates forward, the car moves forward, and other functions are similar and will not be repeated. R9 is an oscillation resistor. The {6}, {7}, {10}, {11}, and {12} pins in RX-2 are the output terminals for functions such as right turn, left turn, backward, forward, and acceleration. R20, D1, C1, and C14 form a simple voltage regulator circuit to provide a stable operating voltage for RX-2, and D2 is an isolation diode.