Horse Power (HP)
Horse Power is a measure of the work output of a motor (electrical or otherwise). The conversion from HP to watts is 1 HP = 746 Watts (Imperial Units).
Hertz
The SI unit of frequency; equal to one cycle per second.
Henry
The SI unit of inductance is Henry.
A coil has an inductance of one henry when a current change of one ampere per second induces a counter emf of one volt.
High-Pass Filter
A filter that passes all frequencies above a specified frequency with little or no attenuation but discriminates or rejects all lower frequencies.