Simple Polarity Tester

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Intro: 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.

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    22 Discussions

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    GitarGr8

    10 years ago on Introduction

    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
    7 replies
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    camaneyGitarGr8

    Reply 8 years ago on Introduction

    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?

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    GitarGr8camaney

    Reply 8 years ago on Introduction

    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.

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    agis68GitarGr8

    Reply 8 years ago on Introduction

     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.

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    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.

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    BrianKT

    10 years ago on Introduction

    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.

    4 replies
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    KitemanKiteman

    Reply 10 years ago on Introduction

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

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    Kitemanlawizeg

    Reply 10 years ago on Introduction

    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.