# AC current measurement question

• DXjohn
In summary, the conversation is about building a firing circuit for oilfield perforating using AC power and the use of a variac to slowly build up voltage. The person is unsure if they can wire an AC ammeter in the circuit in series and is seeking advice on how to properly connect it. They are also considering using a shunt for the ammeter and plan to research more on the topic.
DXjohn
Please excuse my rather dim question but I'm very familiar with homebrewing all manner of DC powered circuits but when it comes to AC..I'm in the dark, sorry.

I'm building a firing circuit for oilfield perforating. We will have AC (Generator) so I'm using a variac to slowly build-up voltage to fire the cap/pcord.
I have a AC voltmeter downstream of variac and have an AC ammeter but I've been told that you can't wire it in the circuit in series as you would in a DC circuit?
It is an old simpson panel meter and I'd like to wire it in but I don't want to fry it accidently.

My wiring sequence is:
AC>switch>variac>switch(safety)>voltmeter>cable to well

Does this make sense?
Thanks!
John

DXjohn said:
have an AC ammeter but I've been told that you can't wire it in the circuit in series as you would in a DC circuit?
It depends on the meter. Some have an internal shunt and can be connected directly (in series of course), some require an external shunt. If yours requires the latter, it will indeed fry without it.

moo

moo said:
It depends on the meter. Some have an internal shunt ...

moo

Thanks moo,
I didn't know a shunt was applicable in AC current measurement.
I'll see if I can find a part # on meter and google some.
Thanks!
John

## What is AC current and how is it measured?

AC current stands for alternating current, which is a type of electrical current that changes direction periodically. It is measured using a device called an ammeter, which measures the flow of electrons in a circuit.

## What are the units of measurement for AC current?

The units of measurement for AC current are amperes (A), also known as amps. This represents the amount of electrical charge passing through a point in a circuit per second.

## Can AC current be measured with a multimeter?

Yes, AC current can be measured with a multimeter. Most modern multimeters have a setting for AC current measurement, but it is important to make sure the multimeter is rated for the voltage and frequency of the AC current being measured.

## What is the difference between peak and RMS measurements for AC current?

Peak measurement refers to the highest point of an electrical waveform, while RMS (root mean square) measurement is an average of the waveform over a certain period of time. In AC current, the RMS measurement is more commonly used as it represents the effective or average power of the current.

## What factors can affect the accuracy of AC current measurements?

The accuracy of AC current measurements can be affected by various factors, such as the quality and calibration of the measuring instrument, the frequency and amplitude of the current, and the presence of any interfering electromagnetic fields. It is important to use proper techniques and equipment to ensure accurate measurements.

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