Resistor Terms:

'A', 'B', 'C', 'D/E', 'F-L', 'M', 'N', 'O', 'P', 'R', 'S', 'T', 'V-Z'

Values: Refer to the page on Common Resistor Values, which is on a different section of the site.

Variable Attenuator Symbol
Variable Attenuator Schematic Symbol

Variable Attenuator: A term that could be applied to a passive variable resistor, having a mechanical wiper which is moved across a resistive element. However the term is more often used to refer to an active component; an RF Attenuator, which uses FETs or diodes to adjust the attenuation.

Variable Resistor: A resistor that is not fixed in value. A resistor that may change its value. Also called a Potentiometer, Trimmer, or Rheostat. Companies that Manufacturer Variable Resistors.

Panel mount variable resistor package drawing
Variable Resistor

Varistor: A resistor that changes value with applied voltage. A varistor may also be called a VDR [Voltage Dependent Resistor]. Varistors will have a negative voltage coefficient. Read more on Varistors, also Companies Manufacturing Varistors.

Graphic drawing of a Varistor Symbol for a schematic
Varistor Symbol

Vendor: A company that sells or Manufacturers Resistors.

Vertical Mount Resistor: A type of resistor package that mounts standing up, all leads on one end. A bracket may also be used to secure the resistor into the PWB, leading to the term Bracket Mount. Bracket Mount resistors would be used for high shock and vibration applications.

On-End Resistor
Vertical Mount

Vitreous Enamel. A coating obtained by fusing powdered glass to a substrate, which is used for humidity protection, and found on fixed and variable wirewound resistors.

Voltage Divider: A three terminal resistor used as a voltage divider. The example below shows a voltage divider in a surface mount 1206 package, note the three leads

Resistor Voltage Divider
Resistor Voltage Divider

Voltage Rating: Resistors shall have a rated direct current (dc) continuous working voltage or an approximate sine-wave root-mean-square (rms) alternating current (ac) continuous working voltage at commercial-line frequency and waveform corresponding to the power rating, as determined from the following formula:

Water-cooled Resistor: A high wattage resistor that uses water to cool the device. The water flows via pipes within the resistor to draw heat away from the device.

Wiper: That part of a variable resistor that moves across the resistive element, to change the resistance, as the control in adjusted.

Mil Spec Adjustable WireWound Resistor
Adjustable Wirewound

Wirewound: A Resistor made up of resistance wire, wound on an insulated form. A wirewound resistor may be variable or fixed. Wire-wound resistors are normally used as power resistors. Types of Wirewound Resistors; Heat-Sinked, Phenlic, Ceramic, Flameproof, Enamel, and Silicone Coated.
Note the graphic above depicts an RX33 style Adjustable Wirewound Resistor from MIL-R-19365.

Mil Spec WireWound Resistor
WireWound Resistor Cut-Away View

Zero-Ohm Resistor: [Jumper Resistor]. A resistor with a value of zero ohms. Zero-Ohm Resistors are used as interconnect points on a PWB. They may also be used to tie two circuit points together while in system test so an internal trace may be accessed but removed in the final application, removing the physical test point. When an array of Zero-Ohm Resistors are used in a single package the term Jumper Chip Array may be used. The term Zero-Ohm Resistor is some what of a misnomer in that they will tend to have the same tolerance as any other value in the same package style, so there may be a value attached to a Zero-Ohm Resistor. Also refer to MIL-PRF-32159 SMD Resistors.

Surface Mount Zero Ohm Resistor
Zero Ohms
PC motherboard

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