When an soundcard probe uses wrong polarity on android/chromebooks

In this blog I will review the Virtins Soundcard probe using it on a chromebook. Chromebooks use a 4-pin headphone not a 3-pin connector like PCs and regular laptops use. Here comes the interesting part when measuring a sawtooth wave it was going backwords seen on figure 1

Figure 1 sawtooth in the wrong direction
Figure 2 Sawtooth going the right direction

What can that do to the circuit?

If you are using a 3-prong chromebook or are hooked up to a 3-prong charger you would have to be extra careful where you connect the ground clip. If wrong BANG you can blow your circuit up, break the probe, blow your hand right off(if enough current),make a big spark.

How can I fix it?

You can cut the RCA adapter cord or get a spare RCA Cord with one end RCA female and the other end male(like an extension cord). and solder the wires opposite.. Where the tip of the RCA on one end goes to the shield and the shield to the tip. The polarity is only wrong for Android and Chromebooks. I choose to use 2 extra RCA cords just because the ones on the adapter is short and also be able to unhook it and use it direct carefully if the extra cord exposes it to RF. I think its already correct for apple devices like iPhones and iPads.

Published by Justin Roeder

I am an electronics engineer and computer programmer that has autism. I learned by myself

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