# Resistors

alright I'm a bit confused here I hear about current-limiting resistors and voltage-limiting resistors are all resistors both or are there 2 kinds of resistors? how can I distinguish between them?

There is only only one kind of resistor, you can limit both voltage and current, it depends how you wire them up. If they're in series you create a Voltage Divider, if in parallel you create a current divider.

http://www.kpsec.freeuk.com/resistan.htm

Often, the resistance of a circuit is fixed – or variable, but not under your control. By placing a resistor in series, you affect both the voltage and current. So, by limiting one, you’re necessarily limiting the other. Whether you refer to this as a “current limiter” or “voltage limiter” depends more on your intention. I.e., is it more important to the design that the voltage or current be kept under control?

Use Falstad’s circuit simulator (Google it) and do the simple battery + resistor + LED circuit. See what happens when you change resistor values and the battery voltage.

Any resistance can be considered current limiting in series, and depending on the calculated load it will influence the voltage that appears across the load or a voltage divider in which two resistors give a specific voltage at the common point whic can be considered voltage reducing with a 5v cicuit a 100 ohm resistor in series means that at most 5/100= .05a can flow if the load aftwe the resistor is say 900 ohms the total current wil be .005a and the voltage across tthe 900 ohms will be 4.5 and the 100ohm will drop. 5 voltsy say its an led with a variable resistance over voltage and the voltage drop of the led is 3v the resistor would need to drop 2v and allow. 03a to flow, so 66ohms will drop 2v and allow. 03a to pass since 5-3=2v and 2v /.03 =66 however usually a 220ohm resistor is. Used so just in case the led get shorted out the resistor needs to drop 5v no more tthan.03ma and then 5v/.03ma=166 ohms so 220(common resistor value) is plenty safe allowing 22ma to flow remember ohms law is your friend