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| What are the advantages of a separate terminal for µA mA on a multimeter ? |
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| tigrou:
Some multimeters have 3 inputs terminals, some (usually the more expansive ones) have 4. AFAIK the main difference is that the ones with 3 inputs have the µA mA shared with volt terminal. This page says a non shared terminal is safer (but don't really explain why). |
| rsjsouza:
When you are rotating the selector switch, any mistake that takes you to µA or mA will short the inputs through the built-in fuse. If you are connected to a sensitive circuit, you will damage it. If you are connected to higher power circuit, you will have a blown fuse. |
| wraper:
--- Quote from: rsjsouza on October 26, 2019, 01:32:40 am ---If you are connected to higher power circuit, you will have a blown fuse. --- End quote --- Likely you will have blown meter and probably even blown traces in selector switch, making it irreparable. Fuse is not guaranteed to save the meter. Also implementations in cheap meters often are simply illusion of security. |
| malagas_on_fire:
--- Quote from: tigrou on October 26, 2019, 01:13:08 am ---Some multimeters have 3 inputs terminals, some (usually the more expansive ones) have 4. AFAIK the main difference is that the ones with 3 inputs have the µA mA shared with volt terminal. This page says a non shared terminal is safer (but don't really explain why). --- End quote --- Chances are that with shared uA/mA with V is that if you selected previously uA/mA, do other stuff, forget about it and probe for volts then the scenarios told by rjsouza would occur , shorting circuit and / or the fuse, since the probes are attached to the same functions, but you forgot to change the selector switch for example. With dedicated jack, you are forced to change the probe from V to uA/mA thus reducing the chances of blowing something and makes sense to have high impedance inputs with fusible inputs. |
| Gyro:
A shared mA and voltage jack guarantees that a meter doesn't have a decent CAT safety rating, no matter what you might find printed on the front. Even in low energy circuits, it will soon outweigh its purchase cost in replacement fuses, possible damage and frustration. |
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