Some questions.

Question 1

I'm wanting to hook a device(multimeter) to my PSU that would normaly take 2 1.5v 357A Batteries I believe I would just need to add a resistor to a lead off my PSUs 5v line but I don't know what value I need. Or would I need something like a LM317T? Any help?


Question 2

I'm hacking apart a multimeter for a mod for my case, the LCD thou has a odd interface for hooking to the pcb. Its some kind of conductive rubber bar that just uses pressure to make the connection. It sits on the contacts on the pcb and then the lcd has a lip that has contacts(clear contacts not metal) and the rubber strip gets sandwitched between the two.

My question is......I know I can easily solder wires to the contacts on the pcb but the contacts on the LCD are on glass and there allmost clear and I'm not sure how to connect the wires to that... I was thinking some kind of conductive glue but wasn't sure. Anyone got a clue?


Question 3

Does anyone know of any places that sells conductive glue in the US ie:HomeDepot, Radio Shack, Lowes, Andersons, MicroCenter etc? and does anyone know if the glue adds any resistance?

Question 4

I need 200,400,500ohm pots but have looked through digikey,jameco,mouser and allcorp with out any success
Does anyone know a good source of Potentiometers in the US?
edit: I have found a few 500 ohm and a couple 200 ohm so I really just need to find a 400 ohm.
edit2:Ok seems as though the 400ohm will be hard to find Isn't there a way to use a resistor or another pot or something so I can get a variable resistance from 0-400ohm?


Thanks
Kook

A1) You could use a few (3) silicon diodes in series, as they have a voltage drop of ~0.7V.
Max. forward current for the 1N4148 is 150mA which I think should be enough, and 1A for the 1N4001.
You could use a resistor, but you need to know the current draw of the multimeter to calculate its resistance.

A2) Yes it is possible to use conductive glue (epoxy).

A3) You could probably get a defogger/defroster repair kit at your local autoshop, I'm not sure about the resistance of the defogger/defroster repair kits, but the resistance of epoxy like shieldokit is ~:
Surface resistance: 0.5 Ohm
Resistance per CM2: 0.0025 Ohm
**NOTE** Make sure it is epoxy and not some sort of conductive paint.

A4) Why do you need a 400 Ohm pot?
There might be a better way other than using a resistor in parallel with the pot, or using 2x 200 Ohm pots in series.
BTW: If you put a 2K Ohm resistor in parallel with a 500 Ohm pot you get 400 Ohm.