What is ammeter?
Ammeter is a device by which current is measured in any electrical circuit. It is a very popular and basic electrical engineering devices.
There are various types of ammeter used in industry. For measuring low current mili ammeter is used.
On the other hand in substation high range ammeter is used like 100A because it need very high capacity instrument in a substation.
How to use?
An ideal ammeter has zero resistance. But practically it has very low resistance.
We can say that it must be used in series to measure current in a electrical circuit. Became if we use ammeter in parallel then the maximum current flow through ammeter, since it has a very low resistance.
In above pic a simple ammeter connection is shown. In the circuit a light is supplied by the battery.
So, ammeter is used in series with the light and battery to measure the circuit current.
Types of Ammeter
According to the current ammeter has two types
1. A. C Ammeter
2. D. C Ammeter
As the name suggest A. C ammeter can measure A. C current and D. C Ammeter can measure D. C current.
According to the construction ammeter is categorised into 4 types
1. P. M. M. C type ammeter.
2. M. I type ammeter.
3. Electro dynamo meter type
4. Rectifier type ammeter.
P. M. M. C (permanent magnet moving coil) type ammeter can only measure D. C current.
M. I (Moving iron) type ammeter can measure both A. C and D. C current.
Electro dynamo meter type ammeter can measure both A. C and D. C current.
Rectifier type ammeter can measure only A. C current.
