How do you figure out polarity for some salvaged circuit components, like resistors, etc?

I took some resistors off a board and noticed that the board said positive at one lead but I didn't pay attention so how do I figure out which is which

sort by: active | newest | oldest
Phil B8 years ago
An electrolytic capacitor has polarity and it is indicated on the capacitor with "- - - - - -" or "+ + + + +" down the side near one of the leads. A diode has polarity and has a solid band to indicate the "+" end. If the component is a resistor, there might have been a "+" on the board to indicate that lead was positive with respect to ground so a technician can troubleshoot the circuit, but that would concern the circuit and not the component.
static6 years ago
Uh... The band on a diode indicates the cathode, the negative terminal. I have never seen or read of a board marked with a "+" to indicate anything for a resistor. Unnecessary because the lead connected to ground isn't going to show a voltage potential.
For transistors and ICs, there are thousands of datasheets at Datasheet Catalog.
NachoMahma8 years ago
. Resistors don't have polarity. The + was for another component.
phillyj (author)  NachoMahma8 years ago
On a closer look, the + is more likely for the capacitor next to the resistor. Thank guys. Both answers were helpful