Frequency To Voltage Converter (Tachometer) – Variable Reluctance Magnetic Pickup to Voltage Converter

The circuit shown here is a frequency-to-voltage converter that can be used in many applications. This is a signal conditioner for Variable Reluctance Magnetic Pickup Sensor used in engines or machines to detect the speed by sensing gears’ teeth. The input signal level is 20mV to 28V. The circuit provides 1V (67Hz/Volt) when the input frequency is 67Hz with a 15V power supply. The maximum input frequency is 1Khz. The project was built using LM2907N-8 IC, refer to the datasheet of the chip for more information and various configurations. CN1 connector is provided to connect the sensor or input signal. D1 power LED, CN2 Power input, and Voltage output. Use the formula below to calculate voltage output from the desired frequency input.