How to avoid short circuit by measuring the voltage of each line on the circuit board with a multimeter
Before your test leads make contact with any electronic circuit components when using a voltmeter to measure them, you must first check the multimeter's state. For instance, if you want to test DC voltage, you have to switch to the DC voltage equipment. Depending on how big, the first step is to engage the highest gear. You must change to the proper AC gear if you are monitoring AC voltage. To measure, you must first shift into the highest gear if you don't know the voltage. Adjust the gear as necessary for an accurate measurement after shifting to the highest gear and taking the measurements.The purpose of reminding everyone to verify the multimeter's state is to stop certain people from measuring voltage directly when the multimeter is in the capacitance or resistance region, which could result in a short circuit and the burning of objects. Therefore, you must acquire a numerical habit before measuring anything, i.e., you must verify the multimeter's gear state and only measure after making sure it is accurate.
First, let's address the topic's primary question: How can I prevent short circuits by using a multimeter to measure the voltage of each line on the circuit board?
1. A multimeter tip as sharp as possible
When I was still in school and studying, I imitated my brother's behavior and polished all of my multimeters' metal front ends very sharply. The smallest amount of the sharp multimeter tip can touch the circuit board. It can prevent the pen tip from being excessively thick during the measurement of particular small-area patch components, preventing unintentional contact between adjacent contacts. So, if you worry that polished test leads are susceptible to oxidation, some retailers have already considered it and offer specific gold-plated test leads for sale.
2. Convert spare black pens into crocodile clips by gathering them.
A spare alligator clip can be made by cutting the black test lead, the hand pen's tip, and a pair of extra test leads. Of course, you may get ready-made ones, with red and black pens, if you don't want to make them yourself.
Determine if the component of the circuit board that needs to be measured is DC voltage or AC voltage before you start measuring the voltage of the circuit board. If it is DC voltage, first switch the multimeter's gear to the one for measuring DC voltage, and then take a black pen in one hand and another in the other. Consider the red pen; the grounding terminal is the black pen. Find the closest potential grounding point that is simple to put and touch. The grounding point is typically a sizable circuit board. The circuit to be measured is then measured using a different red pen.At this time, measuring some fine chip component circuits is made easier by a multimeter's sharper tip. As we mentioned previously, if holding the test leads independently with two hands is difficult, you can link the black test leads with crocodile clips and attach the crocodile clips to the circuit board with the spare test leads. The red test lead may continuously measure the whole DC circuit at the ground point.
If you run into a particularly thin circuit and don't have a test pen tip that is sharp enough, you can find a sewing needle and wrap it around the test pen tip with a thin copper wire that isn't insulated, which also allows measurement.
When measuring without an alligator clip or when it's unclear if the AC voltage is high or low, take care to take two test leads in one hand, much like you would when measuring the AC mains voltage circuit with chopsticks.
The goal of this procedure is to maximize safety. If two hands are used to hold a test lead for measurement, the position between the two hands is the heart, which is extremely dangerous in the event that the test lead leaks, breaks down via the two hands, and delivers an electric shock.
This procedure is really required. Many people who perform maintenance are aware that the majority of them were powered by 220V AC. I've been electrified personally. Repairing a color TV caused me to unintentionally touch the AC circuit. Fortunately, I only needed one hand for it.
