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LC meter using a PIC18F2550

Most modern DMMs (Digital MultiMeters) have a built in option for measuring values of discrete components including resistance in Ohms, capacitances in Farads and inductances in Henrys. Of course we are familiar with the V=IR rule to measure resistances, but how does the DMM measure capacitances and inductances? Jus the cool guy who shared the Mini-STM32 player made this microcontroller based LC meter to demonstrate the theory behind measuring the values of capacitors and inductors. Jus used a reference capacitor with a known value of 1.0nF +/- 5% and a PLL oscillator with a 48MHz frequency range along with a PIC18F2550’s frequency counter to tune into the unknown value of the component. The project comes with a UI which connects with the PIC18F2550 using PIC’s HID class. Continue reading

PIC based accurate LC meter

LC meter is one of frequent embedded projects. It is simply because most multimeters don’t have an inductance meter and sometimes capacitance. You can always buy a better one where you can find these features but why not to build one even with better characteristics you may need. This LC meter operates as most LC meters – they are based on LC oscillator circuit. By measuring the frequency of serial or parallel LC circuit you can calculate unknown L or C value. As result this project is capable to measure inductance in range 0 nH to 10mH at resolution 2nH, capacitance from 0pF to 10uF at resolution 0.1pF. It has automatic calibration ability and autorange as well. This is great and practical project for any hobbyist. Continue reading

Precise LC Meter on PIC16F84A microcontroller

Almost every multimeter has ability to capacitance measurement ability, but inductance measurement is included in more advanced or specialized multimeters. Especially if you like to work with RF technologies, power supplies, LC measurement capability is vital. Instead of buying one I suggest to build one and have pleasure to use accurate LCD metter built by yourself. Design is very simple so it is easy to replicate. It can measure inductances from incredibly small inductance 10nH up to 100mH and capacitance from 0.1pF up to 900nF with auto-ranging capability. Information is displayed on 1×16 LCD module. Zero out button allows to set initial inductance/capacitance for precise measurement. Project page has detailed description on developing LC meter and putting in to nice box. All you have to do is to assemble circuit and flash the program. If you have some troubles in building it, you may buy kit with preprogrammed PIC microcontroller. Continue reading