Analog LC Meter, back to the past 1996

Nowadays is so easy to build precision digital LC meter with LCD display and microcontrollers.
But, what about 1997? There is my first very precision ANALOG LC METER. Look at this, but
do not fall in love in retro princess from past!!
The analog LC-meter project (AP-LC1) have more then 3% accuracy. Really!
There is no balanced bridge, or very expensive components inside.
We read the value on 100mikroA DC instruments with accuracy scale of 2%.
It is very simple,
only one integer circuit (HEF40106BP). I used 5 from 6 Hex Schmitt Trigger organized
like a independent oscillators: 10Hz, 100Hz, 1KHz, 10KHz i 100KHz. If we want to use a higher frequency (1MHz) we must
find original transistor BSX20 instead BF198.
With digital frequency-meter I adjust the same value. The accuracy of adjusted frequencies is precondition for good accuracy of the
analog LC meter, for measuring of both, inductance or capacitance.
With the rotation of central rotate switch we change the range from 100pF to 10microF or 100microH to 1H.
Another linear switch in the right side of instrument, we change mode of measure (L or C).
More instruction for building of this projects, PCB and schematic you can find in
magazine EMITER (7-8, 1997) on page 30-31.
author, writer to magazine EMITER, D-r Petar Avramovski. I like the retro projects!! 🙂


DSC_5450  DSC_5451 DSC_5453 DSC_5454 DSC_5459 montage


  1. H.Huijnen September 5, 2016 2:03 am 

    Nice and useful, but why not a clear schematic diagram added?

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.