Agentgates´s TPU setup with strange wavehill hump

[Groundloop]

Earl,

If we use 18 volt input on this circuit (max. of what the 4017 can tolerate) then
the maximum current the 4017 can source or SINK is 10mA. The BC337 transistor
has an DC current gain of approx. 200. Now we use your 100K in series with the base.
The current from the 4017 pin will be 0,00018 Ampere. This will result in a maximum
collector emitter current of 0,036 Ampere or 36mA. In this design we want the
transistor to switch at least 100mA so we fall a little short with just 36mA.

Now we use 1K2 as a base resistor. At 18 volt the maximum base current will be 0,015 Ampere.
This is a little over the maximum that the 4017 can source but since we use approx. 50% duty
cycle then this current will be safe for the 4017. 0,015 Ampere will result in a collector emitter
current of 3 ampere. And that will blow the transistor if we haven't used the current limiting
resistors in series with the coil that limit the current to 100mA.

The 4017 can both source or sink current (or charge if you prefer that). I prefer to look at BJT
transistors like collectorâ€"emitter current can be viewed as being controlled by the baseâ€"emitter
current (current control). So when the 4017 switch off then the pin will sink and the BJT will switch off.

So I state again, there will be no "unbelievably long turn-off time" in the transistor.

Alex.

[skcusitrah]

Listen to what Earl has to say GL.

Speed-up capacitors are well known in their application for BJT switching applications (see 2/3 of the way down the page).

Don't be so arrogant to think that you can not learn something new, especially when analog electronics is not your forte.

[teslaalset]

My 2 cents:
Any collector resistor in series with a coil will decrease the steepness of the current curve in the coil, no matter what is interfacing the base of the transistor and the 4017.
Is a less steep current slope allowed in this setup?
I guess the steeper the current increase the better.

[agentgates]

@Everybody

I am ready with the coil and stop here with the experimenting and moving to design a complete driving circuitry with ordinary devices, variable duty cycle on each channel. I'll test it in simulator, build it on the breadboard and test it in reality as well by driving the coils and come back with the results.

[Groundloop]

@skcusitrah,

I DO listen to what Earl has to say. And I'm NOT arrogant, and very willing to LEARN something new.

But we are not here to discuss my person or Earl. We are here to promote free energy. I explained
my reason to why I designed the circuit like it is. I also explained why I did choose to use the
resistor values I did use. It is a shitty little circuit and not important in the long run.

Alex.