The impedance of the magnet coils of a receiver is so great for high frequency oscillations that the latter cannot pass through them; in other words, they are choked off.
Where a wire is wound in a coil the impedance of the circuit is increased and where an alternating current is used the impedance grows greater as the frequency gets higher.
The coils 2 and 3 are made to have high impedance, while 1 and 4 are so wound as to be non-inductive and, therefore, offer no impedance save that of their ohmic resistance.
In this the battery is bridged across the circuit of the combined lines in series with two impedance coils, 1 and 2, one on each side of the battery.
The steady current from the central-office battery finds ready path through the transmitter and the impedance coil, but is prevented from passing through the receiver by the barrier set up by the condenser 8.
The condenser in this case is used to afford a short-circuit path for the voice currents that leak from one side of one pair of lines to the other, through the impedance coils bridged across the line.
Toroidal Impedance Coil] The usual diagrammatic symbol for an impedance coil is shown in Fig.
The impedance coils in this case serve to keep the telephone currents confined to their respective pairs of lines in which they originate, and this same consideration applies to the system of Fig.
In this device an insulating base carries a grounded carbon rod and two impedance coils.
Impedance Changes in Cerebral Tissue Accompanying a Learned Discriminative Performance in the Cat.
Extinction of the learned habit abolished the briefly evoked impedance changes, which subsequently reappeared with retraining.
In operating devices on the above plan I have observed curious phenomena ofimpedance which are of interest.
But the circuit opposes the passage of the currents by reason of its impedance and therefore, to secure the best action it is necessary to reduce the impedance to a minimum.
Then there is the impedance in the armature, enormously augmented by the high frequency.
Now one is apt to think in the first moment that the impedance of the wire might have something to do with the phenomenon.
While many were probably prepared to encounter curious phenomena of impedance in the use of a condenser discharged disruptively, the experiments shown were extremely interesting on account of their paradoxical character.
The electrical resonance is the more perfectly attained, the smaller the resistance or the impedance of the conducting path and the more perfect the dielectric.
Among the various current phenomena observed, perhaps the most interesting are those ofimpedance presented by conductors to currents varying at a rapid rate.
A number of novel impedance phenomena are also shown which cannot fail to arouse interest.
Drop in voltage is proportional to the product of the current and resistance for a direct-current circuit, and the product of current and impedance for an alternating-current circuit.
Impedance is to an alternating-current circuit what resistance is to a direct-current circuit.
In this case the flux due to the armature circuit cannot be eliminated altogether, as sufficient flux must always remain to produce enough pressure to balance that due to the residual impedance of the neutralizing coil.
It consists of reducing the pressure at the field terminals by interposing an impedance coil across the supply circuit and feeding the motor from variable points on its windings.
This coil has a small inductance but it is enough to offer a largeimpedance to radio-frequency currents.
The impedance of its secondary will be a quarter of this or 3,000 ohms.
That is, it has too littleimpedance to act like L{a} and so it permits the modulator to vary the output of the oscillator.
Because the receiver would offer a large impedance to the high-frequency current, that is, seriously impede and so reduce the high-frequency current, we connect a condenser around the receiver.
From the watts, the resistance drop can be found, and from this and the impedance voltage, the reactive drop may be calculated.
It is, therefore, important that the users of transformers know the impedance of the apparatus used, in order to determine whether two or more transformers will operate satisfactorily in parallel.
These components have a phase difference of 90° and are represented graphically similar to the impedance components.
If the impedance volts, as measured, be divided by the primary current, the impedance of the transformer is obtained.
By applying to the primary circuit twice the impedancevoltage of either transformer, full primary and secondary current will circulate through both transformers.
The primaries are connected with one bucking the other, and a voltage equal to twice the impedance voltage of either transformer inserted in the primary circuit.
With connections as shown, and with the full load current, the voltmeter indicates the impedance volts of the transformer.
A copper rod allows the discharge to pass too quickly and produces a violent shock, whereas iron offers more impedance and allows the flash to leak away by damping down the oscillations.
Impedance diagram for circuit (of above example) containing inductance and capacity.
Construct the impedance diagram in the usual way as in fig.
The impedance may be called the combination of: 1.
The resultant reactance being due to excess of capacity, the impedanceline AC' falls below the horizontal line AB, indicating that the current leads pressure.
It is the impedance of a circuit possessing resistance, inductance, and capacity.
Reactance, may then be defined with respect to its usual significance, that is, inductance reactance, as the component of the impedance which when multiplied into the current, gives the wattless component of the pressure.
Join AC' which gives the impedance sought, and which by measurement is 29.
Constructing a parallelogram with dotted lines AD and CD, it is evident that AC is the resultant of the two components AB and BC, or its equal AD.
Reproduction of oscillograph record of wave form of alternator with one coil per phase per pole.
In circuits having both inductance and capacity, the tangent of the angle of lag or lead as the case may be is the algebraic sum of the two reactances divided by resistance.
Here the resistance is taken at zero, but this would not be possible in practice, as all circuits contain more or less resistance though it may be, in some cases, negligibly small.
The return wire is used sometimes on alternators that furnish current mostly for lighting work.
Alternating current trip coils have relatively high impedance and impose a heavy volt ampere load on the current transformers.
They have relatively high impedance and impose a heavy volt ampere load on the transformers.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "impedance" in a variety of sentences. We hope that you will now be able to make sentences using this word.
