You mean the circuit layout is inadequate for tiny inductance measurements, or there is no circuit diagram supplied?
The layout isn't too critical, as you can null-out the test fixture strays. Most of all it has to be stable so it doesn't drift during measurements. I have a small piece of PCB with banana plugs attached that fits onto the unit and holds IC socket pins for small inductors. To calibrate (null) the unit I short the adapter with a wide, thick shunt wire, measure the base frequency and cal frequency, then replace the short with the inductor to me measured. It can resolve the inductance of the shunt depending on how far you push it into the sockets so you have to be a little careful if making relative measurements.
The circuit is in EMRFD book. Not sure about the copyright, which is why I did not reproduce it. If you like I can ask W7ZOI about putting up the diagram.
Regards,
Alan
24th February 2010 03:55
Paul Debono wrote ...
I just cannot see a proper circuit for the nanohenry tester ??
24th February 2010 13:41
Alan Yates wrote...
Paul,
You mean the circuit layout is inadequate for tiny inductance measurements, or there is no circuit diagram supplied?
The layout isn't too critical, as you can null-out the test fixture strays. Most of all it has to be stable so it doesn't drift during measurements. I have a small piece of PCB with banana plugs attached that fits onto the unit and holds IC socket pins for small inductors. To calibrate (null) the unit I short the adapter with a wide, thick shunt wire, measure the base frequency and cal frequency, then replace the short with the inductor to me measured. It can resolve the inductance of the shunt depending on how far you push it into the sockets so you have to be a little careful if making relative measurements.
The circuit is in EMRFD book. Not sure about the copyright, which is why I did not reproduce it. If you like I can ask W7ZOI about putting up the diagram.
Regards,
Alan