Is the black ground and red pens of a multimeter in a circuit a potential point at any circuit location?
First of all, to explain the significance of the black pen ground, in our electronic circuits, the ground on behalf of the zero potential, that is, the reference point, higher than it is a positive voltage, lower than it is a negative voltage, let's say, our building, with the ground plane as a reference point, the top of the ground floor, first floor, third floor, and so on, and the basement, that is, the negative ground floor, the negative two floors, and so on.
Here clear, let's look at the topic: the black pen grounded (reference point), then the red pen for measurement, is the circuit of this point of the voltage, showing positive is positive voltage, showing negative is negative voltage.
Another thing to note is that: a circuit sometimes have more than one ground, which must be clearly distinguishable, such as our isolated switching power supply or charger, there is a hot ground (high voltage ground), cold ground (low voltage ground). Measurement should be careful to find the right ground.
The red pen connected to the positive black pen to measure any point is also a potential point, it measures the voltage difference between the two test points, the circuit also has a positive power supply as a reference point, PNP tubes are used the most.
Generally yes. But some circuits have two grounding points on them. For example, power supply circuits have a primary grounding point and a secondary grounding point. Choose the grounding point when measuring.
