Resistors 101: a non-technical explanation

eiodotcom —  May 10, 2012 — 4 Comments

Continuing on in our emphasis at making electronics easily accesible and understandable, Eio presents a non-technical explanation of resistors.

What is a resistor? What does it do?

American resistor symbol

A resistor is an electronic component whose purpose is to “resist” (oppose) the flow of electrical current. Resistors are most commonly used in electronic circuits, which are devices that allow electric currents to flow. says, “because resistance is an essential element of nearly every electronic circuit, you’ll use resistors in just about every circuit that you build.”

Resistance is measured in ohms (Ω), where the relationship between current, volts, and resistance is represented by ohm’s law. PlaywithArduino states that to understand resistance, one must understand voltage and current, as defined here:

  • voltage (V) is the measure of the strength electric charges are attracted between the two points
  • current (I) is the measure of how many electric charges are moving per unit time between the two points.

Resistors dissipate power by resisting or limiting the voltage and thus bring down the electricity flow. If a resistor dissipates too much power, it will burn up. Be sure to check the amount of resistance it can handle, often denoted by 1/8, 1/4, 1/2, 1, and 2 watts.

What are resistors used for?

Xicon 3.3 Ohms 1/4 Watt Carbon Film Resistor

Resistors, according to, are used in the following areas:

  • Plate resistor (usually a load)
  • Cathode resistor (usually for biasing, sometimes a load)
  • Grid resistor (to limit ultra HF response)
  • Screen resistor (to limit screen current)
  • Bias resistor (to keep the grid at a constant DC level, often zero or ground)
  • Voltage divider (to cut down the signal level, particularly in high gain amps)
  • Part of an RC low-pass filter (to both lower the voltage and reduce the ripple in the “downstream” parts of a power supply)

So visit our Eio site for all your resistor needs!


See also:


4 responses to Resistors 101: a non-technical explanation


    This is really interesting, You’re a very skilled blogger.

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  1. Breadboards 101 « EIO - May 15, 2012

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  3. Inductors 101 « EIO - June 2, 2012

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