Transformer

[markz]

I just got ripped off at canada.newark.com
The product arrived today Tuesday, Feb. 2, 2016 by courier
Sure it was fast, a few days and its here.

Feb 2, 2016 NEWARK Pur... $32.77
Jan 31, 2016 NEWARK Pur... $6.21

Something felt fishy when the payment of $6.21 went through, but no mention of shipping. I thought it may have been free. But still I had a feeling something wasnt right. I would not have guessed they would randomly charge any amount for shipping without prior acknowledgement. I wished my balance was not at $65 on that prepaid Visa. I thought at most I would get an email about s/h price. Well, I paid $10 more then the #2 place on my list, which was $20 s/h.

Lesson learned!



I'm still pissed off though!
Damn bastards, I'm gunna buy a few more and have my visa balance right at that amount. Show them bastards!
I'm gunna get my monies worth out of them!

 

[e-beach]

I could work on the center tap...you would have to add resistance to reduce to 9v.

Why do you need 9vAC?

 

[markz]

 

[markz]

I feel dirty!

 

[e-beach]

OK, let me ask you this, does that 9vac rectify to dc?

 

[e-beach]

Ok, I was looking at the schematic and there is trace of un-rectified 9v that goes to pin 5 of ATMEGA328-PU micro-controller.

If you really want to save a few bucks get the Hammond transformer an build a resistance circuit into both the undrectified 9v and the rectified side. You will have to research the resistor values that you need to accomplish the task. Also account for the heat generated by the resistors.



Does this link help?

http://www.amazon.com/BLOCK-AVB-TRANSFORMER-ISO-9VAC/dp/B011NAKFNW

 

[Punx0r]

I don't know what this 9V will be supplying, but the open circuit voltage of a transformer is higher than its nominal voltage (40-50% IME). IIRC nominal voltage is delivered at nominal load (10VA or whatever).

 

[markz]

I am mad, I need to punch something!

 

[e-beach]

http://www.avdweb.nl/arduino/hardware-interfacing/spot-welder-controller.html#h3-circuit-description

 

[markz]

Shoulda bought at ca.mouser.com or b&e electronics for the transformer.

 

[Gregory]

This sounds like it will be quite a learning experience for you which is great. But if you want to save money, get the JP welder.

I am confident a 10Vac transformer is fine, if that is the easiest to find just get it. If you bought the PCB it may not fit.
The 7805 will handle it fine, and for the the zero volt crossing signal the micro has internal diodes on the pins that will clamp to Vcc+0.5V (the 1M resistor limits current) .

2VA means a physically small transformer, low power, you can get a bigger one if that's all you can find, it won't force more current into the circuit.

 

[markz]

Oh well, time to move on.

JP Welder, yeah I thought about that, almost bought it too.
No I dont want lead acid batteries in my house thanks.
I dont know if its cheaper or not, I think the method I am doing is a little cheaper, then the JP DIY kit. With the rip-off con artists it will be about equal now, still who wants extra batteries hanging around. I never liked that part of it. Great idea though, ingenious actually, that gentleman is quite smart.

 

[Punx0r]

Wait, why not just use a plug-in 9V power pack (wall-wart)?

That part of the circuit just looks like a regulated 5V power supply for the IC, expect for the tap before the bridge rectifier, which looks like it's delivering 9VAC 50/60 Hz to pin 5 of the IC? The pinout suggests pin 5 can be configured either as an analogue input or a PWM output.

A search through a suitable junk pile of electronic/computer equipment may turn up a 9VAC plug pack. 2VA is very little, almost anything would do.

 

[markz]

Now I just need a microwave transformer, I just email an electronics repair store to see if they got anything.

I will cruise the alleys for an old-school heavy 1000W+ microwave.

I was going to buy one off the classifieds but I need to save money now. Everything will be squared up if I can get a freebie huge ass 1500W transformer, or two exact same microwave transformers in series or parallel.

The self gratification will be worth it for a complete running unit.

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I tallied up the parts ready for order from ca.mouser.com and it came to $23.11CDN

parts from online source 44.80E= $68.95CDN - This could easily have been reduced tremendously with a bread-board and ebay purchases. The only part I would have needed - Programmed ATMEGA328 €8,95 plus €8 s/h. so $26CDN.

plus I am sure there is a way to get the transformer required off of ca.mouser.com for around $6, but mine totalled ($6.21 for the part + $32.77s/h) which is a butt hurting $38.98CDN

My total is $131CDN, which would have been $98.23CDN if I knew what transformer I could have substituted. And a total of $50 with more frugal measures. Like buying copper rods, holders and bread-board off ebay.

No batteries required like the other method that I almost bought.

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Here are some pics, I know the ATMEGA is put in the socket holder.

 

[e-beach]

All the microwave transformers I have found around here are not suitable for tab welders. Not heavy duty enough. Although I have an old car battery charger with a transformer that might do the trick. Don't be afraid to expand your scope for your search for a large transformer. Good luck with it!!!



Edit, Ps....I just bought a microphone pre-amp with a 9v ac power supply. Sooooooo.......just as a thought......

http://www.ebay.ca/itm/9V-AC-Charge...768311?hash=item566a6dcd37:g:YWUAAOSwEK9UKMdq

 

[markz]

From: Alex
Sorry for the late reply one voltage is 4kv dc or frequency is 2450 MHz n the manufacturer date is 1974 the second one is 1480 w and manufactured 1993

Emailed him back said I'd take them both. Not to sure what "4kv dc or frequency is 2450MHz" means. I think perhaps Alex's english skills are bad, or the sticker is rubbed and smudged. For some reason, bad english people sell junk for cheap and not just chuck it.

 

[e-beach]

......... For some reason, bad english people sell junk for cheap and not just chuck it.

.........They see some value in it. Probably because they are poor and need the money.