Impedance Variation Detector.

[SteveT]

I would dearly like to make the following circuit but I am finding it extremely difficult to locate the Inductors and some values of Capacitors unless I want to buy £250 worth etc. It is a very old circuit I know. Does anyone have a more up to date circuit that I would have more chance of making.

Any advice would be gratefully received.

Cheers, SteveT

 

[colin55]

All the inductors in the circuit you have provided are very common values and you can always put two in parallel or series to create a new value.
You add the inductance value of each inductor when placed in series, just like resistors.
Two eqaul inductors in parallel produce half the inductance.

The same applies to capacitors - they can be placed in series or parallel.

For capacitors, two equal capacitors in series produces half the value of either.

Two equal capacitors in parallel produces a value twice the value.

That's why you are never stuck for a resistor or capacitor value in electronics.


Colin Mitchell

 

[RadioRon]

I would dearly like to make the following circuit but I am finding it extremely difficult to locate the Inductors and some values of Capacitors unless I want to buy £250 worth etc. It is a very old circuit I know. Does anyone have a more up to date circuit that I would have more chance of making.

Any advice would be gratefully received.

Cheers, SteveT

This is quite an old circuit. Can you tell us what you would use it for?

In any case, I found this up-to-date circuit that does the same thing as your circuit only using modern ICs. It operates at 1Khz instead of 10KHz but may be OK anyways, or it can be scaled up to 10KHz very easily.

https://www.electro-tech-online.com/custompdfs/2009/02/microohmmeter.pdf

 

[SteveT]

Dear Colin and Ron

Thank you very much for your prompt replies. I hope that you do not think that I have lost the plot when I tell you that the reason for wanting the circuit is to connect it to a large House Plant! By monitoring the plant during the day and night the output will be connected to a motor that will make a small buggy or light system (have not decided which yet) to switch on and off.

Wacky I know, but I have thought about this off and on for some quite considerable time. You will probably be thinking that I need to do a bit more thinking!

Anyway, thanks for your time it is much appreciated.

SteveT