My Motors got me to Tap into Radiant Energy

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JohnS,

Thanks for the advice. I found a faulty resistor (of all things?!)I and am proceeding.

Is it possible to use a ceramic or crystal resonator to produce a certain frequency (like 1M&z) to run a FET driver? If so, that might simplify my particular objective once I experiment with it to know just what I need to acheive to produce the desired outcome.

Almost there,

Bob

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JohnS,

I now have a saw tooth pulse coming out of sect. C, but only 1-2mV at pins 3 & 6. Sect. D gives a flat dash, no up and down at all. Also, neither pot changes anything. I will post pics of scope shot on Photobucket at:

Pictures by bobfrench - Photobucket

Thanks for all your help,

Bob

[JohnStone]

Hi Bob,
sorry for your problems. What you measure is no sawtooth but definitely capacitive crosstalk from your signal section D.
You should have the very same signal (real sawtooth = long ascending and instant descending) at transistor collector, U1A pin2 and U1B pin 7.

The saw tooth shall end at the very level of U1A pin 3.

Are you shure your op amp works with 5V supply?

Please verify this and post pics from scope but make shure that we know the time set and the amplitude set.

• Pic from all pins showing any movement
• DC voltage from all pins not moving.

We will get your baby running!
JohnS

[john_g]

Help with components

@JohnStone or anyone who knows!

I'm just putting together the parts order for John's PWM, 2 items I would like help with please.

Can you recommend a PNP transistor make/number for the current source part of the circuit. Sorry this may seem basic.

I have some Toshiba K3176 MOFETS, 30amp 200v, will these switch ok for 12volts or should I buy another type of FET? I will be using the 555 ctt to drive the FET.

Thanks in advance

Regards

John

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JohnS,

Good to hear from you! I will try to work on this soon. I built another circuit that I am adding the NE555 driver and FET on to and I need to try it out today or tomorrow.

What are you refering to by "op amp", the 393?

BTW, if a circuit shows a 555 with pins 6 and 2 connected and a wire coming off the middle of them, does it matter if I run a wire from 2 to 6 then out, or does the last wire need to be between and equal-distant from pins 2 and 6? In the past, I have run a wire diagonally across the bottom to connect 2 ands 6, or 4 and 8.

Thanks, friend. Hope all is well with you. Have a good Thanksgiving (or maybe that doesn't apply),

Bob

[JohnStone]

...Can you recommend a PNP transistor make/number for the current source part of the circuit. Sorry this may seem basic.

I have some Toshiba K3176 MOFETS, 30amp 200v, will these switch ok for 12volts or should I buy another type of FET? I will be using the 555 ctt to drive the FET.
...

PNP i.e. 2N2907 / BC327, BC328 but any small signal transistor as pnp will do.

your K3176 is fine. Not very fast but moderate. It is switched on above 5 or 6 Volt so if the 555 has 12V supply you will drive it fast enough.
200V is a concern. You easily will get a coil to 200V if you stop current suddenly. So the 12V is not important but the inductivity and the max current will produce overvoltage if stopped.
Imagine a flywheel. Not the accellerating force is important but the weight (= inducitvity)and the speed (max currrent) if you stop it suddenly.
Use a neon parallel to D and S as protection. So start with short pulses up to the point where neon lights up then take a second one in series and prcoceede again.

Nevertheless be prepared to replace them because of damage if you pulse seriously.

[JohnStone]

...What are you refering to by "op amp", the 393?
BTW, if a circuit shows a 555 with pins 6 and 2 connected and a wire coming off the middle of them, does it matter if I run a wire from 2 to 6 then out, or does the last wire need to be between and equal-distant from pins 2 and 6? In the past, I have run a wire diagonally across the bottom to connect 2 ands 6, or 4 and 8.
Thanks, friend. Hope all is well with you. Have a good Thanksgiving (or maybe that doesn't apply)...

• Oh sorry I should have said compartor U1a / U1B
• It is OK to make them as short as possible as you do it at bottom. If the wire needs to go further it does not matter where it starts exactly. This applies for small amperage only.
  If one of the pins is an 555

[john_g]

PNP i.e. 2N2907 / BC327, BC328 but any small signal transistor as pnp will do.

your K3176 is fine. Not very fast but moderate. It is switched on above 5 or 6 Volt so if the 555 has 12V supply you will drive it fast enough.
200V is a concern. You easily will get a coil to 200V if you stop current suddenly. So the 12V is not important but the inductivity and the max current will produce overvoltage if stopped.
Imagine a flywheel. Not the accellerating force is important but the weight (= inducitvity)and the speed (max currrent) if you stop it suddenly.
Use a neon parallel to D and S as protection. So start with short pulses up to the point where neon lights up then take a second one in series and prcoceede again.

Nevertheless be prepared to replace them because of damage if you pulse seriously.

John

Many thanks for the advice. Can you suggest a better FET to use rather than the ones I have, or should I be looking at 600V +?

Regards

John

[JohnStone]

.....Can you suggest a better FET to use rather than the ones I have, or should I be looking at 600V +?....

600V seems to be OK.

Any type I suggest could be not available in your area. You might want to scavenge some PC PSUs. There you find those guys up to 900V mounted ready on a heatsink along nice diodes. Along that you have a switch, fans and a nice casing...... Casing is important if you have higher voltages later on in order to give you and your loved a chance to survive

BTW: see Nice work but the drivers shall be as near to FETs as possible and conneced with THICK wires. At the pic mentioned above you see at right hand a copper bus bar protruding from the bottom of the PCB - that's GOOD!
JohnS

[Cornboy 555]

Thanks John.

600V seems to be OK.

Any type I suggest could be not available in your area. You might want to scavenge some PC PSUs. There you find those guys up to 900V mounted ready on a heatsink along nice diodes. Along that you have a switch, fans and a nice casing...... Casing is important if you have higher voltages later on in order to give you and your loved a chance to survive

BTW: see Nice work but the drivers shall be as near to FETs as possible and conneced with THICK wires. At the pic mentioned above you see at right hand a copper bus bar protruding from the bottom of the PCB - that's GOOD!
JohnS

Thanks John Stone, i'm pretty sure i will have to pick your brains in the future, if thats ok.
Warm Regards Cornboy.

[JohnStone]

[Cornboy 555]

Don't shoot!



spoken with great humour john, you're a funny man.
think i get what your'e saying, Thanks Friend.

[Cornboy 555]

Sorry John They are FOD 3180 opto,s.

[JohnStone]

[Cornboy 555]

Pwm


Hello John, yes you assumed correctly, no electrolitic, yes guilty.Will fix if i rebuild this unit based on your much valued suggestions.

If you are not already familiar with RM Cybernetics PWM's, could you do me a favour and check out their web site for me and let me know if these units can be used to drive high power fet bank gates directly from battery with resistor? Like Darlington pair maybe?

The pics are one i have that has still survived spikes from directly pulsing coils.AS they are adjustable for pulse width and duty cycle it may be a simple solution for me. Everything you need is in the user manual online.

Yeh i know it's cheating, and that i need to know exactly how things work, but i have a 7 days a week job and dislike spending valuable r&d time on tiny stuff that drives me bonkers.Rather build a nice big high torque, iron based, motor UFO style.

Many thanks Friend, i understand why UFO calls you Sir.
Thanks in advance.