Introduction: Polarity Tester

Picture of Polarity Tester

This tester can be used to check the polarity of any power source, and is therefore very useful when installing automotive equipment, alarm systems or anything else you can think of. Because this circuit is so simple and cheap, even frying one with an over voltage is not a big deal.

Step 1:

Picture of

There are many polarity tester available in market like one above but it is just a waste of parts.

Step 2: BOM(Bill of Materials)

Picture of  BOM(Bill of Materials)

BOM(Bill Of Materials)

1. green led

2. red led

3. 330 ohm resistor(optional)

4. soldering iron

5. solder

Step 3: Soldering Led

Picture of Soldering Led

solder positive terminal of green led to negitive terminal of red led and negitive terminal of green led to positive terminal of red led

Step 4: Soldering Resistor(optional)

Picture of Soldering Resistor(optional)

solder 330 ohm resistor to led in series to prevent led from burning

Step 5: Enclosure

LUC VOLDERS made enclosure for this in tinkercad


Luc Volders (author)2015-01-30

Not only did I made it. I also designed an enclosure for it in Tinkercad and provide you with the STL files on my webpage:

Thanks for this. A simple but very usefull design.


Luc Volders (author)2015-02-07

Hey guys,

Simple but so obvious that I missed it:

You can use this design also as a cable tester. Just put the polarity tester in series with a battery and a cable or wires you want to test. Simple but effective !!!

Look at my website for some examples:

amberrayh (author)2015-01-26

Thanks! This would be very useful!

About This Instructable




Bio: Electronics tinkerer | Android Developer | Chatbot Developer | Embedded Hardware and Software Developer | Electronic Engineering Student|
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