Thought I could do it...

Started by Noplasticrobots, October 15, 2005, 10:23:43 PM

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johngreene

I think your numbers look right. A diode looks like a short once the forward voltage has been reached. And yes, all your grounds should connect back to the negative strip on the breadboard. Ground = Negative  just as +9V = Positive. The two connections are commonly referred to as the "Supply Rail". So all "Grounds" get connected together and all "+9V" get connected together. It's cleaner schematically to show them as individual points with common labels rather than have them all connected together on the page.

--john
I started out with nothing... I still have most of it.

Noplasticrobots

Based on what I'm reading, everything should be right on my circuit, but I'm still shorting. Do you think there's a possibility that I have a bad component? Bad being beside the fact that everything is from radio Shack.  ;D
I love the smell of solder in the morning.

Transmogrifox

Yes, it's possible that you have a bad transistor.

First thing to check:  Is your transistor in correctly?  Stick the transistor into the breadboard, all leads in a straight line from top to bottom as you look at it.   Now orient the leads so that the round side is facing to the left.  If you were holding the breadboard perpendicuilar to the table like reading a book, then the transistor pins top to bottom are as follows.

top:  Collector  (junction of resistor, capacitor...)
middle:  Base  (junction of 2.2M resistor--or 2 X 1meg for you)
bottom: Emitter (connected to battery negative--which is ground)

If this is how you wired it, then this is good.  Go buy one of those cheap multiple transistor packages from Radioshack and pick out the 2N3904 and 2N2222 transistors since either will work in this circuit.

Things appeared correct from what I could see on your breadboard (but it was hard to tell where the transistor leads were connected the way it was).  I know I can't tell you it's right when I can't verify everything I would like to see in the photo.
trans·mog·ri·fy
tr.v. trans·mog·ri·fied, trans·mog·ri·fy·ing, trans·mog·ri·fies To change into a different shape or form, especially one that is fantastic or bizarre.

johngreene

Quote from: Noplasticrobots on October 18, 2005, 07:11:45 PM
Based on what I'm reading, everything should be right on my circuit, but I'm still shorting. Do you think there's a possibility that I have a bad component? Bad being beside the fact that everything is from radio Shack.  ;D

Can you explain what you mean by 'shorting at the diodes'? One side of the diodes is ground. You can also just remove the diodes and then test the circuit, without the diodes you will have a booster.

--john
I started out with nothing... I still have most of it.

Noplasticrobots

#24
When I say "short at the diodes" I only mean nothing shorts until I hit the diodes (going in order of components). I removed the diodes and tested for continuity and still came up with a short. I double checked my transistor with your instructions Transmogrifox, and with the back of the box and it's placed correctly. I'll upload a picture of my board later and hopefully get this whole thing straightened out!

Thanks for all the help so far everyone! :)
I love the smell of solder in the morning.