RECTIFIER
An electrical device used to change AC power into DC power. Also known as a converter. A battery charger is a rectifier.

RESISTANCE
Resistance to flow of current in a conductor, measured on ohms. This is an important concept. Resistance is often introduced into electrical circuits, to achieve certain effects. See Ohm's Law.

REEFER
Refrigerated trailer with insulated walls and a self-powered refrigeration unit. Most commonly used for transporting food. The refrigeration unit needs to be turned on and off many times, calling for a reliable solenoid like our electronic solenoid, that can withstand millions of cycles. More on the electronic solenoid.

RETREAD

1. In trucking, a rebuilt tire. Retreading isthe  cause of much controversy, but is a practice which is well-established. It is even mandated for US government vehicles (EO 13149). the Tire and Retread Information Bureau has an informative website. 

2. Picturesque word used to describe an officeholder (eg: Secretary, Treasurer) who has held that office before. A retread is often an older person who is graciously filling in because no-one else can be found to take the job.

RHEOSTAT
A variable resistance used to provide a variable current output. Rotary switches are a convenient way to provide this. Such switches are often used as lighting dimmers or to vary the output of a heater. Check out the many different types that we make!

RPM (Revolutions Per Minute)
Measure of the speed at which a shaft spins. Most often used to describe engine crankshaft speed. Indicated by a tachometer.