Muller Dynamo

[lasersaber]

@Arthurs

Hi lasersaber

    Your video is very good, because my English is not good, not exactly understand your explanation, About generator coil connection, please tell me the picture below, A, B, C, D which one is correct?

Thank you very much
Look forward to your new progress!

I went from Figure B to Figure A.

[e2matrix]

Change the 10k resistor to 20k
This circuit is the simplest you can have
If you killed some transistors already then check or replace the hall too.
I have abused this type of circuit and never killed a transistor or component in the circuit.
You can have much better circuits but for any simple experiment this is good enough also more components more power used...
Success!

Just to clarify the original circuit seems to have a 100 Ω resistor.  Was that actually supposed to be a 10K Ω resistor?  This could be important for those who already have the circuit built and running since it appears gyula was saying current draw can be reduced significantly by changing it to a higher value.  I am assuming a typo at this point and anyone using that original drive circuit may want to change from 100 Ω to 10000 Ω or maybe even 20000 Ω to avoid a lot of extra current draw or blown transistors. 

[romerouk]

Just to clarify the original circuit seems to have a 100 Ω resistor.  Was that actually supposed to be a 10K Ω resistor?  This could be important for those who already have the circuit built and running since it appears gyula was saying current draw can be reduced significantly by changing it to a higher value.  I am assuming a typo at this point and anyone using that original drive circuit may want to change from 100 Ω to 10000 Ω or maybe even 20000 Ω to avoid a lot of extra current draw or blown transistors.

I was talking about the resistor from few posts before where I can see a resistor of 10k to the base of the transistor.
I was not using that, i had a resistor on the input to the hall but yes u can have a resistor to the base too but I think 10k is too low.I was suggested 20k to the base.I have never tested it like that.
yes my input resistor was 100ohm

[teslaalset]

Here is a link on how to make an inexpensive oscilloscope...hope this helps someone else out.

http://markbowers.org/home/crt-oscilloscope

Regards...

http://www.dealextreme.com/p/ds0201-2-8-lcd-pocket-mini-oscilloscope-v1-5-complete-kits-micro-sd-tf-card-slot-39749
or
http://www.scoob.net/oscilloscopen/dso-nano-mini-oscilloscoop.html

Or just google mini oscilloscope or mini DSO

[i_ron]

Just to clarify the original circuit seems to have a 100 Ω resistor.  Was that actually supposed to be a 10K Ω resistor?  This could be important for those who already have the circuit built and running since it appears gyula was saying current draw can be reduced significantly by changing it to a higher value.  I am assuming a typo at this point and anyone using that original drive circuit may want to change from 100 Ω to 10000 Ω or maybe even 20000 Ω to avoid a lot of extra current draw or blown transistors.

As originally drawn the 100 ohm resistor is in the supply to the Hall switch.

This in no way protects the hall output transistor.

Without the coil resistance connect your DMM, on the 10 amp scale, from the base to ground and note that it comes close to blowing the 10 amp fuse (7 to 9 amps)... all with out hurting the TIP42. With a 12 volt battery there is 12 volts on the base. Without a base resistor it is a bomb, waiting to happen!

Correct me if I am wrong but I believe this circuit was originated by konehead to switch a FET, woopy picked it up and substituted the transistor. This circuit will work better with a FET as a FET is a voltage device whereas the TIP42 is a current device. (read AMPS)

This circuit works by grounding the 12 volts that is on the Base to ground with a Hall switch. The current is limited solely by the sink capabilities of the tiny transistor in the hall. Adding a resistor between the hall and the base will cause the circuit to stop working if the resistor is too large.

Chris's mod is redundant in that there is already 12 volts at the base of the TIP42 and so the added resistor does nothing. Increasing the 100 ohm in the original circuit only limits the supply to the hall. Most halls have a built in voltage regulator anyway...so the 100 ohm does what?

This circuit is a gross misuse of parts and should be avoided. Use a hall switch properly, it is all there in the spec sheets. A Hall switch puts a mA logic signal, learn what this means and how best to use it.

First pic: original circuit

Second pic: suggested circuit. (or TC4426...fet is IRF3205)

Ron