Below schematic depicts the design of a Simple Wireless Car Tachometer Circuit to be used for measuring car’s engine speed. Simple Wireless Car Tachometer Circuit – Components and Parts List:
R1, R2, R9 _____ 1K 1/2 W Resistor
R3 ___________ 47K 1/2 W Resistor
R4 ___________ 10K 1/2 W Resistor