One long while ago I bought a capacitance/ inductance meter. I had a thought how to do this for the DIY user. It starts off with this premise:

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does anyone see any obvious flaws with this idea?
I will come up with other ideas for this project and post them here.

 

After borrowing a LCR bridge decades ago and about to venture into SMD I said to hell with this big old gear and got SMD smart tweezers and advise anyone to do the same.
There are now many types available of varying capability and after recently upgrading to a newer version I would highly recommend these for all passive component testing:
https://www.aliexpress.com/item/1005004239869204.html?
Select 3rd image that includes the test PCB populated with precision components.

 

Next brain fart:

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The counter would be this one.

 

Talk about bad smell, the above design stinks. It would need at least 10Khz to give a decent resolution. Leaving the counter in the dust.

 

One long while ago I bought a capacitance/ inductance meter. I had a thought how to do this for the DIY user. It starts off with this premise:

View attachment 316797​

does anyone see any obvious flaws with this idea?
I will come up with other ideas for this project and post them here.

The time constant is L/R.
If L=1uH and R=1kohm, t~1ns

 

A while back I came across a very simple circuit with a bistable multivibrator, where the feedback on one side was the inductor. The inductance is inversely proportional to the frequency of oscillation. Same idea.

 

A while back I came across a very simple circuit with a bistable multivibrator, where the feedback on one side was the inductor. The inductance is inversely proportional to the frequency of oscillation. Same idea.

any chance you could get a schematic?

 

I'm not sure of the TC=L/R, As the resistance increases the TC goes down.

See the link:
https://www.electronics-tutorials.ws/inductor/lr-circuits.html

 

any chance you could get a schematic?

Here are a couple of circuits with voltage or frequency output for the inductance values from a few hundred uH to 10mH.
https://sound-au.com/project121.htm

 

Not absolutely sure this will work, but I do know you like 555s. I think that if you take the astable circuit with the resistor from output to pins 2 and 6, replace the resistor with the inductor, replace the capacitor with a resistor, it should oscillate at a frequency proportional to R/L.

 

The thing that is bending my brain I am having trouble thinking in terms of current instead of voltage. I have gone down this rabbit hole before as evidenced by some of my really older threads. I am convinced in my head there is some way to do this simply with a minimum of components.

 

Brain fart #3:

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I'll never test this but I needed a fresh approach.

 

I'm not sure how good it is but Amazon has a LC meter that is very affordable, I have a much older velleman model, not sure if they still sell it. I'm dropping this thread, I would still like to know how they do it.

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