The ammeter is equivalent to a resistance point in series with the meter head, and the voltmeter is equivalent to a resistance in parallel. What are the functions of the two resistors

The ammeter is equivalent to a resistance point in series with the meter head, and the voltmeter is equivalent to a resistance in parallel. What are the functions of the two resistors

The ammeter should be equivalent to a resistance in parallel with the meter head. After parallel connection, the ammeter will be connected in series with the electrical equipment. When the current of 1mA is applied to the ammeter, the full scale will be indicated. This is the direct connected ammeter. In fact, it is often necessary to measure a large current, which requires making a larger range of ammeters. For example, if a 1mA ammeter is changed into 100mA, it can be changed into a larger ammeter as long as a resistance is connected in parallel, The name of this resistor is shunt, and the scale should be changed to 0-100 ma. After parallel connection, the total resistance of the ammeter is one hundredth of the original, and the current passing through this resistor accounts for 99% of the total current, If the current of 100 a is measured, the resistance with smaller resistance value needs to be paralleled. The wire used in 100 a electric appliance is very thick. It is inconvenient to connect such thick wire directly to the ammeter. If the shunt resistance is used, just lead out two small wires from the shunt and send them to the ammeter, If you have an ammeter and the measuring range is not suitable, you can use the above algorithm to change the resistance value of the shunt and multiply the indicated value by a factor