Resistance is the measurement of a material’s property to reduce electrical current flow. The value of resistance is measured in ohms. Resistors come in many different forms so we will be identifying the most common types for diy projects. I have included a variety of these in the attached photo alongside some complimentary parts for comparison.
The 1/4 watt through hole resistor is a classic format useful for diy projects (top left). The resistance of a common resistor is fixed. You will need to stock up on a few different values so I will be publishing a more detailed parts buying guide in a future article.
Next we will look at close relatives to the common resistor, potentiometers (top center) and photoresistors (bottom left). Both of these have the special property of variable resistance.
Potentiometers are manually tuned variable resistors. Larger formats are referred to as a “pot” for short or “knob” because they are tuned by hand frequently and panel mounted. Small potentiometers are called trimpots and they are usually found low profile on a pcb. Trimpots are good for applications that require precise yet infrequent tuning. A small screwdriver can be used for adjustment, but there is no knob or shaft for your fingers to turn.
Next we have the magical photoresistor. Unlike common resistors and potentiometers, photoresistors can be used as sensors because they are light sensitive! When light increases on the sensor, resistance decreases. Photo sensors are common in many electronic instrument circuits such as tremolo, compression, and theremin like controls.
When paired with an LED (bottom center), photoresistors are called optocouplers. The combination of the two parts is useful for modular control of a circuit from a secondary circuit while keeping the two circuits electronically isolated. We will go into detail with optocouplers in a bunch of future tutorials including a modular CV controlled cassette deck and some cheap little diy VCA modules!
You will find electronic symbols for the parts we covered in this article below along with complimentary parts and some simple circuits to get you thinking about possible applications. Try to do a bit of research on these parts on your own and we will expand on this basis with some of my favorite diy music electronics projects soon! Thanks for your support! Let us know what simple resistor based projects you are working on in the comments!