Ammeter Sentence Examples
The capacity of the condenser is then altered until the maximum current, as indicated by a hot wire ammeter, is produced in the circuit.
There is therefore a certain ratio in which any current passing through the ammeter is divided between the shunt and the working wire.
In its simplest form an electromagnetic ammeter consists of a circular coil of wire in which is pivoted eccentrically an index needle carrying at its lower end a small mass of iron.
Such an instrument is called a soft-iron gravity ammeter.
If these conditions are not fulfilled sufficiently, the ammeter will not give the same indications for the same current if that current has been reached (a) by increasing from a smaller current, or (b) by decreasing from a larger current.
Such an instrument is called a shunted movable coil ammeter, and is represented by a type of instrument shown in fig.
A steady continuous current is then passed through the ammeter and low resistance, placed in series with one another and adjusted so as to give any required scale reading on the ammeter.
The potential difference of the ends of the low resistance is at the same time measured on the potentiometer, and the quotient of this potential difference by the known value of the low resistance gives the true value of the current passing through the ammeter.
I had the ammeter made up with a 200 amp shunt, by the helpful people at Adverc Ltd.
A shunt is resistive device used to generate a small signal voltage to display current on a moving coil ammeter.Advertisement
Immediately on my return from Great Britain, I sent the unrestored ammeter for restoration to Vintage Restorations.
Finally the fuses were put in and we checked the digital ammeter on the control unit.
Such a test is made by determining with an accurate ammeter or watt-meter the current or power supplied to a circuit for a period measured by a good clock and comparing with this the actual reading of the meter 2 See Journ.
This can be then compared with the observed scale reading and the error of the ammeter noted.'
Hence devices for detecting the oscillations in the antenna are merely very sensitive forms of ammeter and voltmeter.Advertisement
In this last case the shunt need not be contained in the instrument itself but may be at a considerable distance, wires being brought from the shunt which carries the main current to the movable coil ammeter itself, which performs the function simply of an indicator, 3.
The instrument therefore does not begin to read from zero current, but from some higher limit which, generally speaking, is about one-tenth of the maximum, so that an ammeter reading up to io amperes will not give much visible indication below i ampere.
A much better form of electromagnetic ammeter can be constructed on a principle now extensively employed, which consists in pivoting in the strong field of a permanent magnet a small coil through which a part of the current to be measured is sent.