HENRY.--The inductance in a circuit in which the electromotive force induced is 1 volt when the inducing current varies at the rate of 1 ampere per second.
HETERODYNE RECEPTION.--(1) Receiving by the beat method. (2) Receiving by means of superposing oscillations generated at the receiving station on the oscillations set up in the aerial by the incoming waves.
HETERODYNE RECEPTOR.--See Receptor, Heterodyne.
HIGH FREQUENCY CURRENTS.--See Currents, High Frequency.
HIGH FREQUENCY RESISTANCE.--See Resistance, High Frequency.
HIGH POTENTIAL CURRENTS.--See Currents, High Potential.
HIGH VOLTAGE CURRENTS.--See Currents, High Potential.
HONEYCOMB COILS.--See Coils, Inductance.
HORSE-POWER.--Used in rating steam machinery. It is equal to 746 watts.
HOT WIRE AMMETER.--See Ammeter, Hot Wire.