An ammeter is a device used to measure electric current in a circuit. It is typically connected in series with the circuit and has a very low resistance in order to minimize its effect on the circuit.
A voltmeter is a device used to measure the voltage difference between two points in a circuit. It is typically connected in parallel with the circuit and has a very high resistance in order to minimize its effect on the circuit.
To construct an ammeter, you will need a low resistance shunt and a sensitive galvanometer. The galvanometer is connected in parallel with the shunt, and the shunt is connected in series with the circuit. The current passing through the shunt will create a voltage drop, which is measured by the galvanometer and converted into a current reading.
To construct a voltmeter, you will need a high resistance resistor and a sensitive galvanometer. The resistor is connected in series with the galvanometer, and the combination is connected in parallel with the circuit. The voltage drop across the resistor is measured by the galvanometer and converted into a voltage reading.
It is important to use the appropriate resistance for the shunt and resistor in order to ensure accurate readings. Additionally, the galvanometer should be sensitive enough to accurately measure the voltage or current being measured. It is also important to ensure proper connections and avoid any short circuits.