Use for the Tesla Switch

[nvisser]

Jetijs
Very impressive data
Your scope shots are between collector and emitter and also than show the high voltage drop over the transistors. 6 to 7 volts.
With a voltmeter I also measure about 7v over the transistors although that is an average voltage. I will pulse the optos by hand and measure again. I am under the impression that if the transistors switch on real hard, that the voltage drop over them will be lower and give us more voltage to work with.

I add a battery in my circuit to 24v. That give me more available voltage for the load as I do not have a 6v motor, but I found that the voltage drop over the C-E also rise
That spikes can be the answer as it was stated that you have to use an inductive load. How did you connect the motor to get dc to it and still get the spikes to the circuit?

[Bit's-n-Bytes]

Bit's,

I noticed from a pinout diagram I found that this PIC has only 3 ADC inputs. I attached the pinout I found. Is this the correct pinout diagram for this chip?
In6 and In7 do not appear to be ADC inputs. (Please bear in mind I have no knowledge of the Pic beyond the pinouts. I have worked with AVR micros and I am thinking of trying something similar using an ATMEGA88 in 28 dip pkg)

Are you planning on measuring voltage on the 4 sense points in your circuit as feedback?
It looks like they will all be referenced to the negative side of battery1. It looks to me that Sense D1 will always be zero because it is also common ground for the pic.

Would the Zener/resistor/cap power regulation circuit be fast enough to filter the spikes from hitting the pic on both positive and negative rails?

What about hooking it up as part of the output load like Leroy did with an auxilliary connection to precharge the output cap on DC side of output bridge where the AC input of the bridge would be connected to J5?

Just some observations. Hope this helps.

Alex

Thanks Alex, I sent you a PM with a link to the manuals and info.
For the voltage supply circuit, I wanted to keep it totally self contained and selected Batt 1 as the source. I am designing this with the intentions that you can have both types of loads such as AC, or DC off of a bridge as you mentioned. As more battefield data becomes available, we can see if there are spikes that we need to filter for on the VDD circuit.

There are a few mistakes in the schematic still, such as the symbols for ground points shown as the test points. This really screwed me up when I went to layout the PC Board, but I have resolved that issue for the sensing.

Thanks so much for your assist.

Bit's

[Jetijs]

Hi nvisser
It is a shame that my scope shots don't kave the scope settings included, will not make this mistake again. My 6v motor is connected between the positive of the battery and the positive of the cap1. Interesting that the motor turns only one way, I could see this using very low switching frequencies, when the cap is starting to charge, more current flows through the motor, as the cap gets full, the current decreases this in turn makes the motor go faster at the beginning of the charging pulse and slower at the end of the charging pulse. The same happens on the cap discharge pulse. But the motor always turns only in one direction, maybe it has built in diodes or something, will check that tomorrow
Jetijs

[nvisser]

On top of your scope screen, it says 5v so I assumed it was 5v /div
I noticed when using a lamp as load that the charge pulse lit the lamp much brighter than the discharge pulse.
Itried to bypass the discharge pulse with a diode over the load so that it goes straight back to the battery but it pulled the batt voltage more down instead of up

[Jetijs]

Right, but at the right (not visible now) I had a setting panel with all the data of interest - peak to peak, max, min voltages, frequencies and duty cycles. Will include them next time

Jetijs

[theremart]

Awesome work Jetijs!

I was amazed that frequency has such a major effect on the spikes.

[ren]

good stuff Jet.

Ive been using a dead battery on my replication, and using a toroidal transformer as the load. If I dont connect up the secondary of the transformer I can hear this "snapping" sound, almost as if there is a spark arcing out somewhere.

Im going to scope it and see what it gives me. I need to get some smaller caps to try a higher frequency.

[stonewater]

good stuff Jet.

Ive been using a dead battery on my replication, and using a toroidal transformer as the load. If I dont connect up the secondary of the transformer I can hear this "snapping" sound, almost as if there is a spark arcing out somewhere.

Im going to scope it and see what it gives me. I need to get some smaller caps to try a higher frequency.

sounds like the insulation is breaking down in the transformer

[ren]

you are probably right Stonewater (Tom?) Ive had problems before with this particular brand of toroid, I think there is a little heat sensitive part on the secondary that can blow out...a safety precaution etc.

It lights up a bunch of LEDs pretty good.

Im gonna try some motors and such, like Jet has. Tried a little window motor I made, it chugs along at about 1.5v on the cap, simple single transistor SG circuit.

[DoubleD]

Hi John and all.

I haven't had time lately to do much but have tried to follow as best as I can.

I see you are looking for was to pull power for PWM...

I have a CCt using Fets/Igbt's (depending on how much power you need)
and everything is isolated There is also a Floating 12v power for the PWM built into it.
I was going to uP control it.
Here is a link to the SCH. check it over and see what you think.

http://img88.imageshack.us/img88/9563/sstsv51aw8.png

i don't have one together right now , I shorted out my working one while testing and haven't had time to rebuild. but it did work great.

Later
Dave

[blackchisel97]

Very impressive Jetijs great piece of work!

Before trying 3 battery switch on larger LABS, I tried small motor as inductive load. There is constant small gain but with motor spinning DMM on the low side goes banana -


Vtech

[wwdotme]

Very impressive Jetijs great piece of work!

Before trying 3 battery switch on larger LABS, I tried small motor as inductive load. There is constant small gain but with motor spinning DMM on the low side goes banana -


Vtech

are you pulsing the switch now Blackchisel or are you just leaving it on for
periods of time then switching batteries?

I think I'm going to start like you have 3 batteries and transistors and
work my from thier.

ww

[Plazma]

Backorders ad Nauseum

Greetings Everyone - I'm new here and this is my first post having followed along trying to learn and absorb as much as possible. I hope to be able to contribute meaningful material going forward - and that is a steep challenge given the quality of all your work and the nice spirit of cooperation in the group.

As I have been culling out 'wounded warriors' from my parts bin, I have been having trouble getting replacements - specifically, MJL21194's. One after another of my goto vendors have reported 'on backorder' - until this evening. I finally got a ship confirmation from Newark. So, if anyone needs this critical part, Newark Electronics might have some in stock with even more coming in in a few days. Both Mouser and Digikey are still backordered. As the economy continues to soften availability (or lack thereof) could get critical as I see a lot of holes showing up (alas, not many from Dirac . . . yet).

Cheers,

Plazma

[blackchisel97]

are you pulsing the switch now Blackchisel or are you just leaving it on for
periods of time then switching batteries?

I think I'm going to start like you have 3 batteries and transistors and
work my from thier.

ww

wwdotme,
I'm leaving on, not pulsing.

Tonight I decided to get closer look @ my full 4 battery switch. As I thought, there is something wrong. When I get the load (60mA 12V grain bulb) to pulse, all batteries are slowly getting down not gaining. When I change d.c. for shorter with delay, load doesn't blink but there is v. slight gain. I had two capacitor banks with a bridge on the output but it didn't work. I measured voltage over and I have 17.6V on one bank and 6.84 on other. On the bridge output variable 1 - 2V. I have H11 in series with LED and 330R to the ground, wonder if I should run them parallel? I think that's the way John did his on the pic. I have to draw this entire circuit on the paper and think over instead of trying to run from my head. I probably goofed somewhere.


Vtech

[Inquorate]

Welcome

Welcome to the forum Plasma


Your post brings to mind a point to consider; if the old transistors can't be found easily, there's no reason not to try a variety of new ones in say a square wave pulsed three battery setup.

Using 12v wall transformers for charge batteries and same discharged battery and load; then determine how effective different transistors are.

Experiment experiment experiment

Love and light