PWM circuit 555

[mscoffman]

Yes that should be ok, If you disconnect the fet. Does the ne555
still run hot? If so the high vcc is at fault. My tendency would have
been to use the orignal circuit with the load moved from the collector
to the emitter of the power transistor. If the signal is not a square
wave then load will see the opposite polarity inverted signal. But the
current drive should be correct. If the ne555 runs hot with the load
disconnected though the bipolar transistor won't help that.

:S:MarkSCoffman

[gyulasun]

so your saying at a 1k resistor where i did in series with the vdc feed for the 555? now where is this cap supposed to go?

you know, this chip is only rated for 200mah, i wonder if that resistor on "vdc in" that i added on the diagram will resolve the issue.. 

thanks for your input, just so i understand your full statement where are you suggesting to add the cap? connected to pins 8 and 4 but still allowing pins 8 and 4 to connect to the positive feed directly? pin 4 if i remember correctly is the reset (either it or 8 one.)

thanks

Hi,  I attached what I thought may clean up the supply input to the 555 if nasty pulses may appear on the battery fed back from the transformer, such already happened with me.
IF you use MOSFET instead of the bipolar transistor it can also happen that the drain-source side high voltage pulse (if any) may leak through to the 55 output via the FET self capacitances that may be several hundred pF to some nF too and you would need to protect the 555 output from it, mainly with series resistor like in the bipolar transistor case.

rgds,  Gyula

[Paul-R]

less than 1khz i believe, but i can assure you its a long ways away from the famous 42.8

i was aiming for 923 as there was some experiments that said that was a good frequency but it didnt do me any good.

It won't.

If you want to split water, you should first try using 42.8khz, as used by
Bob Boyce (along with an octave down, and another an octave down on that).
Stan Meyer and Dave Lawton. Also as used by John Worrell Keely before them.

[Artic_Knight]

yes the famous 42.8 is good but as previously stated the frequency changes a lot with different conditions (temp, electrolyte, plate size, etc) and i didnt want to sit down and commit to a frequency anyways. 923 was convienient so i started with that but mearly needed a pwm for testing.

i figure when i get good and ready to play with frequencies and see if they are useful i will need to know more about the resonant fracturing of water as im going to want to keep resonance despite changes in the cell temp and water contaminants.

first things first, im working this weekend with the circuit again to make sure its running cool, then im finishing my dry cell and testing its production after that if i feel lucky ill try some resonance.

as with many members of this forum i feel the need to take it one step at a time, but i am glad i have many knowledgable people here who are willing to lend some advice! thanks to everyone for their kindness!

[Paul-R]

yes the famous 42.8 is good but as previously stated the frequency changes a lot with different conditions (temp, electrolyte, plate size, etc)...

No, with respect, I think you are wrong. You start with 42.8khz.
That is a given. Everything else can be changed. Achieving this
number is not difficult. It is a matter of using the 555 spreadsheet
and getting the right values for the resistance and capacitance.