You’re get involved with many projects that require to measure the impedance of a component? You couldn’t find the right tool to help you overcome the hassle? Well, in this case, you might want to create a brand new high accuracy digital LC meter.
Digital LC meter, or it also known as the “LCR” meter, is the electronic test equipment, which normally being used to measure the impedance, such as inductance, capacitance and resistance! The digital LC meter started to gain its popularity over the analog type, due to their high accuracy and high input impedance. Some other features like auto zeroing, auto ranging, auto power off and down mode are making the digital LC meter more powerful than the analog LC meter!
This project is based on the PIC16F628 and PIC16F84 base inductance/capacitance, where the measuring range is from 0 to >0.1 uF for capacitance and 0 to >10mH for inductance. The expected accuracy is in between +/- 1% of reading +/- 0.1pF or +/- 10nH.
An LM311 comparator with positive feedback is being used to make a parallel LC oscillator with digital output. By applying the LM311 onto the project, it can oscillate over a wide range of L and C values continuously!