Question about capacitors.

[Wubble]

Hi everyone. I'll start off by saying that I'm completely new to electronics. I've wanted to try doing some small projects for a while, and when I stumbled upon this forum, I decided to finally give it a go.

I found a good tutorial that explained how resistors, diodes and transistors worked, and how to use them in a circuit, but they didn't mention capacitors. I know the princible behind them, but not how to use them in a circuit.

For example, I've been wanting to build a bug zapper. Using a battery to charge a capacitor, and then the capacitor to quickly discharge and zap the bugs.

I made a quick drawing in paint of how I thought it would be.

**broken link removed**

When you turn on the switch, the battery charges the capacitor, and the capacitor discharges when a bug hits.

Have I understood capacitors correctly? Will the capacitor charge, even if the negative pole isn't connected to the negative pole of the battery(when the bug isn't there)?

 

[kiriakos-gr]

First in order to zap something , you need 2.500 volts ..

Second ... check this draw ... https://www.electro-tech-online.com/threads/capacitor-discharge-in-pulses-questions.110207/#post903125

 

[Wubble]

Aha. So I guess both ends of the capacitors will need to be in contact with the battery to charge it. It makes a lot more sense as well, when I think about it.

Anyways, I made a new drawing.

**broken link removed**

This should work, then? The first switch charges the capacitor, the second one just to discharge it if it's charged with no bugs around.
The bug won't be there when it's charging of course.

2.500 volts to zap a bug? I'm not thinking of setting it on fire or something, just kill it. How much resistance could a little bug have?

I guess 1.5 V might have been too little, but 2.500? Wouldn't that be a bit overkill?

 

[SneaKSz]

if you close the first swith(switch 2 off) , the C will charge immediately ( no resistance ) and if you close the second switch ( switch one is off) the capacitor will discharge immediatly ( no resistance ) . If you close switch open and switch two when the C is charged , the bug will die if you make contact .

if you close switch 1 and 2 you'll have a short circuit

greets

 

[audioguru]

First in order to zap something , you need 2.500 volts ..

No.
2.500V is only 2.5V. You need two thousand 500 volts which is 2500V or 2,500V.

 

[audioguru]

You need thousands of volts to zap a bug.
Put your fingers across a 1.5V battery cell. Do you feel the femto-amps or less of current? No. A bug doesn't either.

 

[Reloadron]

For example, I've been wanting to build a bug zapper. Using a battery to charge a capacitor, and then the capacitor to quickly discharge and zap the bugs.

You will need some very cooperative bugs for this to work.

Now as was mentioned bug zappers generally use high voltage, voltages exceeding 2,000 volts in most cases. Although your idea as to using a charged capacitor to zap a bug sounds good and looks good on paper it isn't really practical.

So what to do? Well I would suggest getting an old neon sign transformer and building a bug zapper but like I said you get into working with mains power and subsequent high voltage. Bad things can happen when doing this, especially to someone new who is learning. Now we don't want you electrocuted do we?

Since you have been reading about various components a good start would be using those components in basic circuits using batteries and maybe prove out a little theory. Save a few bucks and invest in a meter so you can "see" things happen. Light a few lamps and focus on simple learning projects. Avoid mains power (wall outlets) and high voltage things that can really ruin your day.

Ron

 

[Wubble]

To clarify, I was thinking of something like this **broken link removed**

not **broken link removed**.

Does that plastic thingie really have 2,500 volts?

Anyways, I guess it might not be the best thing to start off with. It did seem like a fun and useful thing though.

**broken link removed**

Never mind the voltages, would this have worked if I had the proper power?

 

[audioguru]

Your pics show products that produce thousands of volts to zap bugs.
People report that the cheap tennis racket zapper fails when a bug is zapped but stays there shorting the wires. Then the circuit is zapped.

 

[Noggin]

**broken link removed**

Never mind the voltages, would this have worked if I had the proper power?

Yes, that would work if that were a 2000v battery and a cap with sufficient capacitance and voltage capabilities.