Interactions within Ecosystems

A voltmeter is an instrument used for measuring the electric potential difference (voltage) between two points in an electric circuit. It is always connected in parallel across the component or points where the voltage is to be measured. This is because it has a very high internal resistance, which prevents it from drawing significant current from the circuit, thus not altering the circuit's operation.

An ammeter is an instrument used for measuring the electric current (in amperes) in a circuit. It is always connected in series within the circuit, meaning the current flows through the ammeter. To accurately measure current without significantly affecting the circuit's resistance, an ammeter has a very low internal resistance.