Simple toggle circuit?

Ohh... do tell, so a mechanical switch won't work?

We (son and I) hooked up our induction heater to two 12V lead acid car batteries. The "switch" was just a big clip to the battery terminal. I was going to bring home a toggle switch... maybe add some beefy diode (with a series resistor?) to the switch.

There is a lot of energy stored in the induction heater. I was poking around measuring voltages and accidentally shorted the input leads... oops ... I totally vaporized about 1/2 inch (10 mm) of the fat trace that connects the inductors to the input power lead. No other problems AFAICT. (It still works)

George H.

On a sunny day (Mon, 4 Jan 2016 11:06:21 -0800 (PST)) it happened George Herold wrote in :

I used a mechanica lswith till now, but I think it has now had ots best time, get very hot too at 20A

it is a 12V switch, actually marked 12V 16 A, so yo ucan imagine. But the fact that the flyback volgae killed my new 20 A amp meter ,,, I use a new one now and that one is preceded by an 7808 fed via a 75 ohm redistor..

So, big enough switch should work, but I need to protect againt to deep discharge too, and want a timer setting (to bake the eggs) etc etc.

Yes flyback diode is a good idea, how is the RF impedance of a car battery + leads? I digged up some 1uF 64 V electrolytics and these poly caps that can take a punch:

It is easy to blow up these MOSFETs although those have an internal limiting zener, the drain-gate cap will will blow the gate, that is why the zener. The 47k to ground is in case power up and static charge and PIC is tri-state, or gate charged from last time..

Yes mine still works too :-) I am still waiting for that carbon crucible to arrive... Got the water pump (aquarium pump) for the big coil working.

I baked some shrimp on it in the mean time, olive oil, pepper and garlic. It convinced me enough to order a real induction plate for in the kitchen. mmm

Hmm good point, I've got lots of little C&K 5A toggles, but maybe something a bit bigger.

7808? voltage regulator?? I've got to dig up some small value resistors to measure current. (My son admits he's still confused by the whole current / voltage thing... so this may be a good learning experience.)

He wants to heat treat steel. He measures the temperature by heating it above the curie temperature.... (magnets no longer stick.) But at the moment there was not enough power from the induction heater... I was thinking another car battery.... (Will Mom notice when her car clock and radio stations are reset? :^)

George H.

Jim, Tom:

Neat, and I'll try it next time I need a switch de-bouncing toggle. But not for triggering from my slow touch switch output in the current discussion.

Terry, East Grinstead, UK

There was a big thread on this 10-15 years ago with some great and original examples.

I tried to find a searchable usenet archive since google doesn't do that any more. Know of any?

There is also an episode of eevblog where he designs a toggle with 2 FETs specifically to turn power on and off.

It would work perfectly for your _slow_ touch switch... it copes very well with slow rising signals... having the equivalent of Vcc/3 for hysteresis. ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

On a sunny day (Mon, 4 Jan 2016 12:22:02 -0800 (PST)) it happened George Herold wrote in :

Just imagine water flow and water hight? The electrons being the water, and capacitors the vessels.

Very clever, yes that should work. That is the way the Weller magnestat soldering iron works (or was it worked?).

There should be enough for a small metal object, I had no problem heating some strips red hot in a minute or so.

Like this...

...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

I wish!

But many thanks for reminding me and for this comprehensive summary.

When I first read it earlier this evening I was using my iPad. This is how its Safari browser renders the schematics:

Basically unreadable. So I'll study in the morning on my PC with Firefox.

But if they are all triggered by push buttons then presumably they won't be immediately suitable for the current purpose: toggling from the slow rising and rather noisy output of my capacitive touch switch.

Not in my 2nd Edition, so I guess it must be in the 3rd?

A great source. Amongst others, I used Bill's 'CMOS Toggle Flip Flop Using Push Button' several times.

I've just done what I should have done earlier and dusted off my old notes. I first used this toggled touch switch in 1981 and again half a dozen times later. I think the touch section was based on a circuit by R M Marston. But I now see that the main mistake I made in the current version was to precede the 4013 flip-flop with a Schmitt; it should have been a mono. However, I doubt if making that change would fix the instability I described up-thread in my reply to Fred.

--------------------

Fred: Don't have a schematic, and probably no time to draw one, but if I can find the original source I'll post a scan or photo tomorrow.

--
Terry, East Grinstead, UK

It appears that the posts you made via Google aren't showing up on GigaNews rendition of sci.electronics.design ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Yeah I did that, (not capacitor part.. )

Huh, yeah I still use those.. I didn't know they worked on the Curie temperature. Fun... Thanks.

Well I let him have some big ol' hand files...several inches sticking out each end of the coils. It got the middle bit to a dull red glow. You're right a smaller hunk of metal should be fine.

George H.

On a sunny day (Mon, 4 Jan 2016 16:42:05 -0800 (PST)) it happened George Herold wrote in :

On the bottom of each tip is a number engraved in a little discs, it indicates the temperature at which that disk is no longer attracted by a magnet,

been using 371 for many years for repair. That magnet is in the front of the iron and activates a micro switch, causing that ticking sound and its RF interference...

Yep, I got a good instrument screwdriver red hot, but now it has become soft iron, how was it ? heat up and cool down fast to strengthen steel? How did the old sword makers do it?

On a sunny day (Mon, 04 Jan 2016 23:00:08 +0000) it happened Terry Pinnell wrote in :

Or use a HEF4520B, binary counter, it has a Schmitt trigger input for the clock, so all you now need is a small cap. And then you have 2 for the price of 1.

Hardens, not strengthens. You can try plunging it into oil (or water, but that's harder on it). You can also heat it up with charcoal around it (in an conventional oven you can use stainless foil, but I don't think that will work in an induction heater). That case-hardens it by adding carbon.

Plunge the red-hot sword into the body of a slave (no, actually that's BS)

--sp

--
Best regards,  
Spehro Pefhany 
Amazon link for AoE 3rd Edition:            http://tinyurl.com/ntrpwu8 
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On a sunny day (Tue, 05 Jan 2016 02:54:15 -0500) it happened Spehro Pefhany wrote in :

I managed to decode that, but to verify I went up in the URL, a nice site! Thank you.

Thanks Jim, will try it asap. (I think I was looking at the wrong page of your PDF earlier when I concluded it was too complex.)

First step in the shed today though will be to try salvaging as much as possible from what I've already built. Now that I've realised my mistake in using a Schmitt instead of a mono ahead of my 4013 toggle I'll probably try to add the mono by using the LH side of the 4013. But as I said in my replies earlier to Fred and Win, I'm not hopeful that will eliminate the instability.

The upside is that I'm learning (and re-learning) a lot ;-)

Here's the current state of the circuit, the one that worked before I stuffed the parts into the lamp base:

--
Terry, East Grinstead, UK

Thanks Jan, but more solder work!

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Terry, East Grinstead, UK

It looks like this thread could be a useful reference source about 'toggle circuits' (especially button operated types) - at least for me. So here are a few more I've dug out of my files. They probably duplicate some or all of those in Win's long list.

More on Spehro's circuit, apparently my reply to a request here:

More on that ultra-simple Elektor circuit:

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Terry, East Grinstead, UK

Best I can do at the moment. Have never got around to drawing the schematic except by hand.

As I thought, it was from R M Marston. Specifically from his book '110 Semiconductor Projects for the Home Constructor', first published

1969.

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Terry, East Grinstead, UK