Beginner's dilemma

--- The resistance of the resistor is 650 ohms, and the tolerance on that value is +/- 5%.

The first color band indicates that the first significant figure of the value of resistance is blue (6), the second is green (5), and the third indicates that the decimal multiplier ( the number of zeroes after the second significant figure) is brown (1). The fourth band, gold, indicates that the tolerance is +/- 5%. Ergo,

650 ohms, +/-5%.

It's difficult to say whether your charger will make a good power supply since it's designed to charge your cellphone batteries and may supply more than 5V if it's not loaded properly. It also may produce what's called "ripple" which may not be acceptable for a breadboard supply. What kind of test equipment do you have available?

-- John Fields Professional Circuit Designer

That will work. However i would recomend a powersupply with higer voltage if you are interested other things. I guess its ok for simple circuits and digital stuff. Working with audio circuits would often require a more powerful PSU.

Just rember that leds dont like to much current. 20 -30 mA is often the max value. It will work fine with the resistor you have. 5 V / 650Ohms = 7.6mA. You could even wire 65 leds in this fashion and the PSU would still do. ;) Maybe you could wire a similar resitor in paralell to make it brighter. Then the current would be 15.2mA. Now you only could wire 32 leds.

Just remember that leds are polarised devices. If you can feel the flat edge on one of the sides of the diode. That pin will got to the negative (ground) side of the PSU. Hope you have a multimeter.

Have fun.

Anders N. Vinje

650 ohms isn't a standard value, according to my references - the OP should check the colour code again. The nearest standard values to 650 are 620 (blue red brown) or 680 (blue grey brown)

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Peter Bennett VE7CEI 
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--
Good catch. I\'ll bet he got the blue and green reversed, i.e. it\'s a
560 ohm resistor.  Or maybe 15 megohms?^)

Or possibly 750 ohms, also a standard value. It might be as easy to mistake violet for blue as it would be to mistake red or especially grey for green.

Chris

The same thing struck me so I checked my chart

657 is a standard value--for 0.5% or better Of course, it would take more bands. Not sure where the OP got that number.

I wondering if Chris Foley didn't call it right when he alluded to color perception problems.

If you are not yet equipped, buy a small cheap handheld multimeter, analogue or digital, and makes sure it has a diode test and a beeper continuity range. They are very cheap nowadays. Read the accompanying booklet!! RESISTOR values (unwired, out of circuit) are easy to prove by reading the display! No such commonplace thing as a 650 Ohm. Some efficient LEDs are happy running at down to one mA. Caution! You said your power supply is a charger so it might give a much higher voltage (maybe +33%) than it quoted if just driving an LED. But 560r is a safe dropper at 7-8V DC.