LC meter with PIC16F870

The main part of this project is a LCD, PIC16F870 and an oscillator LM311.
The LCD is a standard 2 line 16 chars display connected in 4-wire mode to the PIC.
At the bottom you will find a 4.000 MHz crystal to run the PIC.

The heart of this construction is the LC oscillator based around IC2. The frequency pops out at pin 7 and then enters the PIC at pin 11.
Two relays have been added to make the measurement more automatic, and they will also prevent stray inductance/capacitance.
Many LC meters use manually switches which will be conected with long wires. I prefer relays which will improve the accuracy and keep the stray capacitance/inductance down to a minimum level.

lc_meter

Source: hem.passagen.se

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