Single resistive components being powered directly by a power source is the simplest circuit. 5 volts is a common supply voltage used to power electronics these days, so that is what I will be using.

Resistors:

Limit current through them (and series components) based on the voltage across them and their resistance.

Divide voltage if there are more than 1 of them in series with a supply voltage.

Create heat (wattage)



Similar resistor kit to the one I have. Lots of values at a low price. Affiliate link ad.

Diagram

Video below explains this diagram.

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Video

Electronics course 1 Resistor component limiting current Ohms law and multimeter measurements







Kit that has everything you need to learn basic electronics and Arduino.

The current (I) in amps through a resistor is the voltage (V) across the resistor divided by it’s resistance (R) in ohms (Ω).

An LED wired in the forward biased direction that is in series with a resistor will drop about 2-3V from the resistor (covered in more detail in the next lesson). The resistor value should be chosen so that there is less than 20mA of current to protect the LED. The resistor must also not overheat, which is explained below, and in the video.

Most resistors commonly used in electronics are rated for a maximum wattage of 1/4W (one quarter watt), which is the same as 0.25W. They should however be kept below 1/8W (0.125W) to help ensure that they don’t overheat.

Heat generation and dissipation in watts (W), which is also called power (P), is calculated by multiplying the voltage (V) in volts across a component by the current (I) in amps flowing through it. Formula is P = VI

The top diagram above shows the probe locations to take common multimeter measurements, which I also demonstrate in the video above.





The affiliate link ad above is to a best selling multimeter since the ones I use are unfortunately not being sold anymore. It still helps this site if you click the link, check out the meter and compare it with other meters to see what looks best for you!

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