Question

Voltmeters are always connected in parallel with a circuit component, and ammeters are always connected in series. Explain why.

Short answer

Short answer: Voltmeters are connected in parallel with a circuit component to measure voltage (potential difference) across that component without affecting the current flow, thanks to the voltmeter's high resistance. On the other hand, ammeters are connected in series with the circuit component to measure current, as the same current flows through all components in a series connection. The low resistance of the ammeter ensures it doesn't significantly change the current flow in the circuit.

Step-by-step solution

Understand the purpose of a voltmeter and an ammeter

A voltmeter is an instrument used to measure the voltage, or potential difference, between two points in an electrical circuit. An ammeter, on the other hand, is an instrument used to measure the current, or the flow of electric charge, through a circuit.

Explain the function of a voltmeter

A voltmeter measures the voltage drop (potential difference) across a circuit element. This voltage drop depends on the element's resistance and the current running through it, as described by Ohm's law: V=IR. To measure the voltage without affecting the original circuit, the voltmeter must have a high resistance so that it doesn't significantly change the current flow in the circuit.

Explain the function of an ammeter

An ammeter is used to measure the current flowing through a circuit by measuring the voltage across a known small resistance (typically a small shunt resistor) in series with the circuit. The ammeter must have a very low resistance compared to other elements in the circuit, so it doesn't create a significant voltage drop and affect the current flow in the circuit.

Explain why a voltmeter is connected in parallel

A voltmeter is connected in parallel with a circuit component because, in a parallel connection, the voltage across the components remains the same. By placing the voltmeter parallel to the component, we can measure the potential difference directly across that specific component without significantly changing the current flow in the circuit, thanks to the voltmeter's high resistance.

Explain why an ammeter is connected in series

An ammeter is connected in series with the circuit component because in a series connection, the current flowing through each component is the same. The ammeter's very low resistance ensures that it doesn't create a significant voltage drop and change the current flow in the circuit. By connecting the ammeter in series, we can directly measure the current flowing through a specific part of the circuit.