can i use a 220 ohms resistor in place of a 240 ohms resistor?

seandogue7 years ago
if the design is tolerant to a 10% deviation from expected value.

LED?  prolly, as long as you're not calculating 240 ohms based on maxxing the LED's forward current. If that were the case, you'd exceed the mfg ratings and might let out the magic smoke.
Usually, but that might depend on the exact application.