Which instrument is used to measure the amount of current flowing through a load?

Which instrument is used to measure the amount of current flowing through a load?

• A. Oscilloscopes
• B. Ammeters
• C. Voltmeters
• D. Ohmmeters

Answer: (B)

Current is the measure of how much charge passes a point per second. An ammeter is the instrument used to measure that current. To read the current through a specific load, you place the ammeter in series with the load so the same current flows through both. The ammeter has a very low internal resistance so it doesn’t drop a significant voltage or alter the circuit. If you connected a meter in parallel, it would create an alternate path for current, either bypassing the load or shorting the source, leading to incorrect readings and potential damage. A voltmeter, in contrast, has high internal resistance and is connected in parallel to measure voltage across a component. An ohmmeter applies a small voltage and measures the response to determine resistance, and is used when the circuit is powered off. An oscilloscope measures voltage waveforms; it can measure current only with a current probe or shunt, but it isn’t the standard instrument for simply reading current through a load. So, to measure how much current flows through the load, use an ammeter.

Current is the measure of how much charge passes a point per second. An ammeter is the instrument used to measure that current. To read the current through a specific load, you place the ammeter in series with the load so the same current flows through both. The ammeter has a very low internal resistance so it doesn’t drop a significant voltage or alter the circuit. If you connected a meter in parallel, it would create an alternate path for current, either bypassing the load or shorting the source, leading to incorrect readings and potential damage. A voltmeter, in contrast, has high internal resistance and is connected in parallel to measure voltage across a component. An ohmmeter applies a small voltage and measures the response to determine resistance, and is used when the circuit is powered off. An oscilloscope measures voltage waveforms; it can measure current only with a current probe or shunt, but it isn’t the standard instrument for simply reading current through a load. So, to measure how much current flows through the load, use an ammeter.