DIY : DC 12 Volt Test pen for Vehicle Electrical wiring Check

Posted by kal , Sunday, March 18, 2012 11:11 PM

Create your own DC voltage tester by using a damage AC Test Pen.
Here, I am using a small size of test pen. Sorry, I am forget to snap a photo at the beginning of project.


The above figure, show how I do the connection.
1. 1K ohm resistor are to avoid L.E.D burn out.( soldering to Fuse cap )
2. 2 pieces of L.E.D ( soldering to fuse cap ,tip to tip )
3. Soldering 1 wire to negative ( - ) point ( through small hole at the test pen Holder )


How to Check the L.E.D polarity before soldering it ?
1. Using the Multimeter , set the value to X1 as shown above.
2. Check the L.E.D, connect the positive (+) and negative (-) multimeter probe to L.E.D lead.
3. During the checking,if you found that L.E.D is light on, it's mean the probe (-) is L.E.D positive (+) point
    and the probe (+) is L.E.D negative (-) point

Here are the Completed negative wire connected as negative (-) point

Now, this DC test pen are ready to use for any dc12 volt checking wiring such as for vehicle repairing,etc.