Header image  
Projects 'n' Stuff  
  Home  | Back  |
LC Meter.
The finished project.

This project will prove to be a worthwhile addition to my equipment and was fun to build. What can I say? I love electronics. What I'm finding interesting at the moment is the number of projects using PIC chips that give results approaching lab quality performance at much less than lab quality prices. This is an interesting time in electronics for the hobbyist.
I've also implemented some improvements - using a low drop-out 5v regulator and winding a custom inductor for the reference circuit, to improve stability and measurement error.
Calibration is performed first. Turnon the unit with the switch in the Cx position with no components connected. Press Zero button briefly and the unit should now read 0.0pF. Calibration done.
LC Meter
Measuring capacitance.

Here's a photo showing a 220pF capacitor being measured using a modified IDC connector, allowing a component to be inserted & measured quickly and easily. It also acts as a mini-prototype board, so several components can be added together and measured at the same time to get, say, a desired value. i.e. two capacitors connected in parallel to make a required value of capacitance. Thanks to Paul, VK5AB, for the suggestion, the pcb and the single line display.
Measuring capacitance
Another capacitor.

Here's a photo showing a 2.2nF capacitor being measured. What you thought was a 2.2nF capacitor, here you can see what it actually measures.
Measuring capacitance
Measuring inductance.

Here's a photo showing a 0.54uH (540nH) inductor being measured. Calibration is performed first, with the switch in the Lx position and a short installed on either set of connectors and the zero button has then been pressed. Remove the short and you're ready to measure.
Measuring inductance
Measuring another inductor.

Here's another photo, showing a 3uH inductor being measured.
Measuring another inductance
Schematic and code.

Here's where the original schematic and code can be downloaded:
Original article by VK3BHR includes parts listing and construction details. Digital LC Meter Version 2

    2006 - 2014 S.Spirat 
Another SPIRAT initiative