How to probe a voltage using ps2204A?

hobby2020 · Post by **hobby2020** » Thu Apr 23, 2020 2:42 pm

I have a ps2204A. I was wondering how to probe a voltage using this oscilloscope. I read that the probe has two parts, one is the ground (the one with alligator clip and in black) and the other one should be in contact with where I want to probe. Does the ground mean anywhere with a less potential than where the tip of probe has a contact with? For example in the image below to probe the resistor's voltage where should the ground part of the probe go (the black wire is the ground and the red is the tip of the probe)? Does it matter if I switch the place of the ground probe and the tip of the probe?

If I want to probe the voltage of a polar capacitor can I attach the ground probe to any side of the capacitor and the tip of the probe to other side of the capacitor?

chubby23280 · Post by **chubby23280** » Thu Apr 23, 2020 7:10 pm

Yes it generally makes a difference where you place the ground probe. When we refer to ground in electrical circuits, we refer to the reference voltage from which we measure voltages. If you want to measure the voltage at one point in a circuit with reference to the ground you can place the probe at that point in the circuit and the ground clip to the ground (in the circuit you have provided there it would be the wire connected to the negative terminal of the battery). Since voltmeters (an oscilloscope may function as one) measure the difference in electric potential between two points, you want to make sure you are measuring between the correct two points. If you place the probes where you have indicated on your drawing you will get the voltage that is dropped across the resistor only. There are many analogies for this but its like measuring your height. If you measure your height from the your waist to the top of your head, you will get the height of the top half of your body. If you measure from the bottom of your feet to the top of your head, you will get your total height. In this analogy, if you swap the start point of where you measure from, you start measuring from the top of your head to the bottom of your feet, you should get a minus answer since you are now measuring in the opposite direction. Unfortunately this analogy only goes so far since a measuring tape only shows positive numbers.

Post by **Martyn** » Fri Apr 24, 2020 4:55 am

Putting the ground clip on a point that is not ground can cause a ground loop with potentially hazardous consequences.

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How to probe a voltage using ps2204A?

How to probe a voltage using ps2204A?

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Re: How to probe a voltage using ps2204A?