Hello,

Would anybody be able to tell me why a breadboard would just suddenly die while the power source is still plugged in? I've checked all my wiring and not one wire is loose. :-( I really would like to go forward with building my nerdkit so if anyone has a suggestion, I'd greatly appreciate it. Thanks

Hi Everybody,

I'm so new at this that I've just learned my breadboard when out because the power supply died on me. Just to be sure, I went out a bought a new 9V battery. Came home, plugged it in, and "wa la" it's alive again. So, I've solved my problem. Thanks for not teasing me.

Don't worry about being teased here. Most of us have had those moments too. Glad you figured your problem out.

Rick

nerdgirl-

Get yourself a digital multimeter. At a minimum, it must read volts, Ohms, continuity, and diode testing. Then learn how to use it. The two most important things to learn are this: DO NOT EVER connect your meter, while in OHMS mode, to a live circuit. Always (and never forget) to check your meter settings BEFORE you connect to anything. Lastly, if the meter is not auto-ranging, ALWAYS set the scale higher (or max) than what you expect you will be measuring. After you measure and see where the needle (or count) goes, you can then adjust the scale downward as necessary. If you get this wrong, you can ruin your meter.

Please ask questions. There is no such thing as a stupid question. We've all been there.

BM

Hi BM,

Thanks for your advice. I will definitely be buying a digital multimeter just as soon as I'm able. Also, thanks for letting me know there is no stupid question. I'm enjoying my Nerdkit and want to learn all I can. It's nice to know that there are people like you to help a person out.

No problem. I strongly urge you to go to your local library (it's free) and check out books on BASIC electronic theory. Learn what voltage and current are, and "circle" formulas like EIR and PIE. E = Voltage (sometimes shown as V), I = Current, and R = Ohms. P = Power in Watts. EIR is Ohm's Law. PIE is Watt's Law.

Take a pen and paper, draw two (2) circles (about 1.5" diameter, each). Now draw a horizontal line from edge to edge, across the middle of each of them, cutting the circle in half (top half and bottom half). Next, divide the bottom half into two quarters, but drawing a line from the center of the circle to the bottom edge.

In one circle, write E in the top circle half, I in the bottom left quadrant, and R in the bottom right quadrant.

In the second circle, write P in the top circle half, I in the bottom left quadran, and E in the bottom right quadrant.

Now, pay attention to how the circle is laid out, as regards these formulas (where each letter is, in relation to the others, AND the lines in the circle):

E = I/R
I = E/R
R = E/I

As voltage (E) increases, so does current (I) - in a stable relationship, given a non-changing resistance (R). Because of this a circle formula can be used to derive any one value, if you know the other two.

Watt's Law is no different:

P = I * E
I = P/E
E = P/I

You can test this with a common lightbulb in your house. You know your house voltage (America) is ideally 120VAC. Your bulb says 60Watts. So, realistically, how much current is that bulb drawing in an hour (KwH)?

I = 60/120
I = .5 Amps (aka 500milliAmps)

But how much resistance must that filament offer?

R = E/I
R = 120/.5
R = 240 Ohms.

Now, in this case, R would represent Impedance, a bit more complex than resistance, because we're talking AC, and eventually you'll get their, too. But for the moment, in this idealized example, you can see how useful knowing these things are.

Memorize EIR and PIE- the circles will help you visualize them.

Next time you find yourself looking at any electrical item (lamp, car battery, whatever), take a look at the sticker and see what info it provides- you can learn a lot about the world around you by understanding these things.

Lastly, in electronics, when you look at a number, you're going to want to get used to converting it back and forth from electrical-think:

5.243uF             <-- what in the world?

That is actually 0.000005243 F (F = Farrad).

Here's the key:

X.mmm.uuu.nnn.ppp.fff

X = whole number
m = milli
u = micro
n = nano
p = pico
f = femto

Normally, you'll rarely deal with anything below nano, and usually not more than milli or micro.

Hope this helps BM

Boba, Nice work. AC and impedance are truly a different animal. As long as it is straight resistance, it's pretty much the same as DC but throw in some capacitors and/or inductors and a whole new can opens up.

Then there is the RMS thing... 120VAC in house current is really about 170 volts peak to peak and that also needs to be taken into consideration. Another lesson ...

I added some of this info to the library here under the glossary section.