How do I reduce the voltage on the power cables?

[y0ungsta]

I need help on reducing 5v to 1v or 2v because my cheesey thermal temp checker is about 1.6v. The useage of little batteries kinda sucks and I want to just leave it in my system. :( I know i have to use some resistors, but i don't know how to wire them.

[klosters64a]

I'm sure that you plan to add a Molex "extender" or "jumper" to your main power "daisy chain" that will be dedicated to this thermal probe, or temp monitor.

Then it's a matter of finding out the Amperage that the device requires and choosing the right Resistors that will give you the desired Voltage. This assumes that you have a Multi-Meter or other accurate way to measure voltages.

It's probably easiest to use a Potentiometer or Variable Resistor to dial in the exact voltage needed by the device. This component must be able to handle the Amperage needed by the device, as well as provide the necessary Voltage value. Let's hope that someone who knows how to figure out exactly what kind of a circuit you need chimes in on this thread!

[y0ungsta]

I hope so too.

[Shep]

Actualy you need to get a zener diode rated at 1.5V and build a circuit. Go to radio shack and get a small perf board, a 1.5V zener, and a 1Watt 10 OHM resistor (based on 300mA of current). Use the 5V wire and connect to one end of the resistor connect the zener to the other end of the resistor the line should be closest to the resistor, connect ground to the other end of the zener. connect the hot lead for the temp probe to the junction of the resistor and the zener. connect ground to the other end of the zener and it's done. It can be done without the perf board but won't look as good and will be more fragile. If you have any questions just ask.

[Crazy Jayhawk]

Originally posted by Shep
Actualy you need to get a zener diode rated at 1.5V and build a circuit. Go to radio shack and get a small perf board, a 1.5V zener, and a 1Watt 10 OHM resistor (based on 300mA of current). Use the 5V wire and connect to one end of the resistor connect the zener to the other end of the resistor the line should be closest to the resistor, connect ground to the other end of the zener. connect the hot lead for the temp probe to the junction of the resistor and the zener. connect ground to the other end of the zener and it's done. It can be done without the perf board but won't look as good and will be more fragile. If you have any questions just ask. I have a question.

What's a zener diode? :confused:

[y0ungsta]

It's pretty hard to understand...Can you have a layout picture of it for me because i can't which wire is which since there is - and +.

Thank you :)

[Shep]

Originally posted by Crazy Jayhawk
I have a question.

What's a zener diode? :confused:

A zener diode is a diode that will regulate voltage when reversed biased. when forward biased they act just like a regular diode. It is hard to explain any better with out going into the theory of hole flow and electron flow.

[Shep]

Originally posted by y0ungsta
It's pretty hard to understand...Can you have a layout picture of it for me because i can't which wire is which since there is - and +.

Thank you :)

I would put the picture up here but I don't know how. If you can explain how I will post it if not I can email it to you

[Shep]

I think I have figured out how to post a pic.
http://www.dabros.com/images/shep/voltage_reg.jpg
here is the circuit that can be used.

[y0ungsta]

Shep where can i get a zener diode 1.5 v? Can i use other zener diode from 2.5v-10v ? I tried looking for it but can't find the right one.

[Robbie]

shep's right!! That should work if you can finda 1.5 volt zener. If the shack doesn't have what your looking for (sometimes they do sometimes they don't) they you may have to try an electronics store.

These places are around you just have to look, but WHEN you find one your going to LOVE it. The guys that work there are usually VERY VERY knowledgable. Just tell them what you want to do and they'll probably JUMP at the chance to help you and make some EXCELENT suggestions.

You could try an online store if you can find one. I don't know of any. (guess I should start looking)

Hope it works out for ya.

OH yeah don't forget to not have any bare wiree floating around. Tape everything off, you don't want a short!!

Rob

[y0ungsta]

Thanks rob that's great!