Introduction: Simple Polarity Tester

In this instructable I will show you how to make a simple polarity tester capable of out to about 12vdc.

Step 1: Materials

-4 diode (must at least withstand 12vdc)
-1 red LED
-1 green LED
-1 1k ohm resistor
-perf board
-solder
-soldering iron

Step 2: How to Know How to Position Diode on Circuit Board

You should notice a white, Grey or other color banned on your diode, this is were it goes on a schematic.

Step 3: The Circuit

-D1=Green LED
-D2=Red LED
-D4 to 7=Diode
-R1=1 k ohm resistor

Step 4: Now Your Done!

Now that your done you can use it for any circuit testing under 12vdc.

Comments

author
GitarGr8 made it! (author)2008-03-23

Cool idea, this is a great project for a beginner. I don't think that D4 through D7 are needed in this case because you are using LEDs, which are themselves a type of diode. Try building a circuit like this:

06 2008-03-23.jpg
author
camaney made it! (author)camaney2010-07-29

I need to check the polarity on batteries of 2V, 6V, 8V and 12V will this simple design will work as well or do I have to implement a switch and add different resistances value?

author
GitarGr8 made it! (author)GitarGr82010-07-29

You'd probably want a different resistor for the various voltages and LEDs, but I don't see why this wouldn't work for what you're trying to do. you might want to add a selector switch for the different voltages you are trying to test, each with the properly sized resistor for that voltage.

author
agis68 made it! (author)agis682010-02-27

 Yeah right LEDs are diodes. So we don't need the diode. BUT we need them if we have a non stable charger (PSU)...now we replace the diodes by Zeners . For example if you work with 4,5 V the need a 5v1 zener. Zener protects and reduce the Voltage but no the Amps.

author
Junkyard John made it! (author)Junkyard John2008-08-12

Yar, thar be a circuit like mine instructable: A logc level analyzer

author
Dr.Bill made it! (author)Dr.Bill2009-04-13

Yar me bucco, mine too!

author
Dr.Bill made it! (author)Dr.Bill2009-04-13

this works good to 12v. or so with a 47 ohm resistor.

author
Ben The Builder made it! (author)Ben The Builder2009-04-07

That's what I was thinking, you don't need more diodes you only need the two

author
Sagar Gondaliya made it! (author)2009-06-25

what diodes did you use?

author
steven123654 made it! (author)steven1236542009-06-28

1n4001 if I remember right but it doesn't really matter.

author
GorillazMiko made it! (author)2008-03-23

Cool, but you really want to use macro mode on your camera. It's a little flower icon-- it helps a lot.

author
steven123654 made it! (author)steven1236542008-03-26

I don't think I have it it's a really cheap camera.

author
viacin made it! (author)viacin2008-08-24

How about a new digital camera. :-) You can find some awsome disposable ones with a lot of features for about $20, then do this to 'em :D

http://www.metacafe.com/watch/422124/digital_camera_hack_secret_the_stores_dont_want_you_to_know/

Ye 'Ole KipKay Digital Camera Hack. Mine has got me by for over a year now.

author
MACKattacksnipe made it! (author)2008-07-09

photos are kinda blurry

author
computerwiz_222 made it! (author)2008-04-17

This is essentially a fancy lighting up multimeter. This is actually a really great idea! I can't tell you how many times I will be working in my car and I want to check polarity of some wires or something.

author
BrianKT made it! (author)2008-03-23

Try using macro mode on your camera next time you take pictures that close up. Btw, why do the pictures say they're from 2004? Great concept though.

author
Kiteman made it! (author)Kiteman2008-03-24

It's either an old idea, or his camera's clock is set wrong.

author
Kiteman made it! (author)Kiteman2008-03-24

(I'd guess the latter, since he apparently made the whole thing at twenty past midnight as well.)

author
lawizeg made it! (author)lawizeg2008-04-07

i don't want to sound stupid...but what's polarity?

author
Kiteman made it! (author)Kiteman2008-04-08

It's which way round the current flows (the + and - on batteries). Also, some components, like diodes (including LEDs) and some kinds of capacitor, only work when the current flows through them one and not the other.

author
lawizeg made it! (author)lawizeg2008-04-08

Thanks, Kite~~dude~~man.

author
Kiteman made it! (author)Kiteman2008-04-09

You're welcome.

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