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View Full Version : Help with bedini circuit, with pics and labeled


adamo21
09-08-2010, 07:31 AM
Ok guys, im having problem with this circuit. I tested each diode and resistor with my multimeter on diode test mode, I also tested my transistor and everything works correctly.

When I disconnect everything from the circuit and connect the power coil start to the battery + and the power coil - to the battery negative, my coil heats up and creates an electromagnet which then repels my mangets. But when its hooked up to the circuit I get no electromagnet effect or oscilliation.

I have tried different resistances on he variable resistor from 100ohm to 5-10k ohm, nothing works.

I also tested the voltage through the power coil when the circuit is setup and im getting the correct voltage through the coil while using the circuit, so it appears the negative isnt going through the coil and creating the electromagnet effect.

Here is a pic of my circuit.

http://img687.imageshack.us/img687/5198/circuitmarked.jpg

Any ideas?

adamo21
09-08-2010, 07:45 AM
Here is the circuit schematic im using.

http://img195.imageshack.us/img195/5862/draftmancircuit.jpg

torpex
09-08-2010, 09:31 AM
Hi adamo21

You have tried to reverse the connections of the Trigger coil?

Regards

adamo21
09-08-2010, 10:21 AM
Tropex I have tried reversing both the power coil and the trigger coil but not just one or the other. I will give that a try and report back.

ren
09-08-2010, 10:42 AM
that neon is in the wrong place. Should be connected before the diode.


Disconnect your coil and place it under the rotor.

Pick power winding and connect directly to a battery. If polarity is correct (on the electro magnet AND the rotor magnets) it should push the rotor away. If it sucks it in (attraction mode) you need to reverse the connections.

Once you have correct polarity keep the power coil connected to the positive of the battery, the other end (which you were briefly connecting to the negative) goes to the collector.

The same end of the trigger wire goes to the EMITTER, the other end will go through the resistance to the base. If you cant get it to work with 100 ohms on the base its one (all) of 4 things.

A) Not enough turns on the coil to turn the trigger on.

B) Not enough induced current from the passing magnet (either not strong enough or too far away from the coil)

C) Transistor/resistor/diode faulty

D) Faulty connection (cold solder joints or such).

Regards

adamo21
09-08-2010, 10:46 AM
FINALLLY!!!!

I finally got it! The problem was I had the neon bulb disconnected so the neg from the battery wasn't connected to the diode #2, once it was connected the electromagnet became fully functional and repelled the magnet...

Thanks for the help ren and torpex!! Much appreciated. This was my first circuit ever built and it took me like a week to figure all of this out. Now I can actually read a schematic and have an understanding of how it works, huge learning experience. Thanks guys.

Duncan
09-08-2010, 11:32 AM
Hi Adamo a bit frustrating when your project doesnít work! The NPN transistor is basically a switch in this circuit. All silicon transistors switch when 0.7 v (or there abouts) is between the base and the emitter the emitter being negative w.r.t the base obviously. Transistor Circuits (http://www.kpsec.freeuk.com/trancirc.htm)
So when your magnet is passing the (in this case) trigger coil you should be able to measure circa this voltage with your multimeter. If you canít then at least you have a point to start testing for the fault. It will also indicate if your trigger coil is connected the right way round. Good luck with it!