Connecting Components to External Equipment

jgrant333

Joined Jan 9, 2009
3
Hello all,

I have real difficulty imagining how I will connect my devices (such as resistors, transistors etc.) to external test equipment. For example I have to connect a microbolometer (which essentially is a resistor with a high temperature coefficient of resistance) to both a current source and a lock-in-amplifier. However I only have two connections to do so. How on earth do I connect my microbolometer to both my DC current source and lock-in amplifier?

Just to be clear I envisage on wire bonding from my resistor to a PCB and then interfacing the PCB with my external equipment via BNC PCB mount connectors (or something similar).

Also does anyone have a guide on how to understand circuit diagrams? When I look at one I find it hard to even know how to understand what is going on!

Thanks

jgrant333

Joined Jan 9, 2009
3
I've attached an image of what I'm trying to connect.

I realise a 4 point measurement would be a much more accurate measurement however due to space limitations I have to settle for 2 connections to my resistor. In any case the series resistance of the connections is <<< than the resistor's resistance.

I need to supply the resistor with a constant current while meaasuring the output voltage with a lock-in-amplifier. How do I connect these two components when I only have two bond pads?

Many thanks,

James

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beenthere

Joined Apr 20, 2004
15,808
If the resistance pictured goes to ground, then it's just a matter of attaching the constant current source and the lock-in input to the other pad. The lock-in will see the voltage across the resistor relative to circuit ground.

jgrant333

Joined Jan 9, 2009
3
If the resistance pictured goes to ground, then it's just a matter of attaching the constant current source and the lock-in input to the other pad. The lock-in will see the voltage across the resistor relative to circuit ground.
The constant current soure has two leads, one for "high" and one for "low". The resistor must be connected to both these leads. That being the case how do I connect my lock-in amp? Do I just add another pad (see attached diagram) for the input of the lock in amp.

Note I hope to wire bond from each bond pad to a PCB.

Thanks,

James

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beenthere

Joined Apr 20, 2004
15,808
That should work, especially if "low" and circuit ground are the same.