describe how you would connect an ammeter into an electric circuit correctly
Answers
Answer:
series
Explanation:
ammeter must be connected in series as the total current flows through it
Answer:
Let’s consider DC based circuits first. Ammeters then are connected in series (like in a sequential chain) between the power supply or source (not necessarily the same) and the power drain (or the circuit load). Since we are talking about a DC circuit, the power to the circuit is first turn OFF to prevent sparking (in a large current situation) and to allow the measurement driven modification to be made. I usually measure if any voltage is present at the power leads where the current measurement will be done. The reason for this is to see if there are any sneak power circuits feeding the circuit under test. The circuit is then broken (or opened with either a switch, a jumper plug removal or simply disconnected) on the (usually) positive side of the supply. If you have to physically cut the positive feed wire, make sure that you can reconnect it so that no short exposed wires remain after the measurement.
Make sure that you use an ammeter that will be able to appropriately measure the load. As an example if you are trying to measure a current with a supply current in the range of 7.5A, connecting an ammeter that is designed to measure 0 to 1A, then the instrument will most likely burn out. Professionals use ammeters that have switched multiple current range or are using measuring meters that can be shunted with the appropriate range shunt. The meter positive connection (usually a red wire or probe) is connected to the positive source of the power supply. The negative wire or probe (usually a black wire) is connected to the power load (where the circuit was cut/interrupted or disconnected previously.
Assuring that everything is done properly, then depending on the meter used turn the power supply on again. As a note if you are using a digital multi-meter, the instrument should be turned on FIRST, perhaps set on the highest current range. Turn the power supply back on and observe the current indication on the meter.
As mentioned by other fellow Quorians, if using a current probe, then it is easier but less flexible. For AC based circuits, there are no polarities to worry about but the range issue has to be factored in. The rest is more or less the same procedure.
I have been doing electronics, measurements plus remote customer support to solve power supplies issues over the phone for many years and I have seen (and experienced) my share of mishaps, errors, absence of knowledge/hands-on experience. I have seen accidents (some life threatening) so I am sharing a thing or two to help.