Muller Dynamo for experimentalists

[penno64]

Hi Ron,

As you may have noticed, I have already posted many questions about this experiment in
the MD thread.

The explanation is simply this -

This is the effect - master the effect and apply it to whatever you wish !

What is the effect - Pulling a load from a generator and having the generator speed up instead of,
as with our generators, lug down.

Hope this helps

Penno

[poynt99]

There is nothing really wrong with this circuit imho. It is basic, simple, and obviously does the job exactly as Romero uses it.

Usually, it is a good idea to have a base resistor for any power transistor, especially when driven by a voltage source. In this case however, it's driven by more of a current source of sorts, so this may not be so critical.

If one wants to ensure limiting of the Hall transistor to the max specified 25mA, the base resistor R should be about 450 Ohms, so 470 will do nicely.

The 100 Ohm in series with the Hall supply may not be necessary, unless it is felt that protection is required from high voltage transients that my be present on the supply line, otherwise, this 100 Ohm resistor will only limit the base current drive to the Hall transistor, and thus slow down the switching.

Romero has the right idea with the 20k (10k or smaller would be better) he showed on his recent post. This should help speed up the switch-OFF of the Hall transistor, and hence in turn, the drive transistor.

.99

[i_ron]

There is nothing really wrong with this circuit imho. It is basic, simple, and obviously does the job exactly as Romero uses it.

.99

But the circuit you posted is not what Romero used.

The circuit I spoke about was minus the base resistor.

The bottom line here is as Romero admitted...

" ...where the simple one PNP transitor was using 230ma to drive a motor coil this one in the same circuit used only 90ma."

A better circuit is two and half times more efficient.

Ron

[poynt99]

But the circuit you posted is not what Romero used.

The circuit I spoke about was minus the base resistor.

The bottom line here is as Romero admitted...

" ...where the simple one PNP transitor was using 230ma to drive a motor coil this one in the same circuit used only 90ma."

A better circuit is two and half times more efficient.

Ron

The circuit he used without the base resistor apparently worked fine and still allowed for the motor to be looped. 

Agreed there are better circuits, and it would seem his 4-transistor (MOSFET?) circuit is just that.

I know you were referring to the circuit without the base resistor, and as I alluded to, I'm not certain whether adding the base resistor will reduce the current consumption or not. That may depend on the conduction mode or modes the TIP drive transistor is operating in.

.99

[i_ron]

Agreed there are better circuits, and it would seem his 4-transistor (MOSFET?) circuit is just that.

.99

Well this is open territory here, I thought at first that the four "things" made up an H bridge... but why then do the two yellow wires from the 'output coil' go over to this circuit board?

Could it be that he is coil shorting from this board also?

R