my home made inverter circuit

[madshaman]

Yep you did dude, can see it clearly in picture 271 from your first set of pictures.  Easy thing to do, no worries.

[c4757p]

To back myself up more, the only longer-body transistors I've seen like the ones in that video were Japanese 2SC ones, which are E-C-B.

The good news for you is that unlike many ways you can hook things up wrong in a circuit (especially an inverter), those transistors are most likely not damaged and will work fine when you switch them around 

[madshaman]

Pretty much all bjts in that package have base in the middle, which can confuse you because the large mosfets you've been dealing with are ordered differently.

Are those electrolytic caps?  If so, one of them is backwards too.  The +ve end should be connected to the 680Ohm resistors.  Edit: never mind, they are clearly polyester film, my illiteracy.

[c4757p]

Pretty much all bjts in that package have base in the middle, which can confuse you because the large mosfets you've been dealing with are ordered differently.

Look at the video screenshot he posted - they really are connected that way. 2SCxxxx and a few other oddballs are E-C-B.

[Nickk2057]

Pretty much all bjts in that package have base in the middle, which can confuse you because the large mosfets you've been dealing with are ordered differently.

Are those electrolytic caps?  If so, one of them is backwards too.  The +ve end should be connected to the 680Ohm resistors.  Edit: never mind, they are clearly polyester film, my illiteracy.

by the way.. those are bi - poler caps

[madshaman]

Pretty much all bjts in that package have base in the middle, which can confuse you because the large mosfets you've been dealing with are ordered differently.

Are those electrolytic caps?  If so, one of them is backwards too.  The +ve end should be connected to the 680Ohm resistors.  Edit: never mind, they are clearly polyester film, my illiteracy.

by the way.. those are bi - poler caps

My bad, I should have seen the "PET" clearly written in subsequent pictures (I'm used to those being big and square)

[Nickk2057]

totally alright... anyways.. i tried the PN2222 chips on it.. but this time it just stays on... no ocilation

[madshaman]

totally alright... anyways.. i tried the PN2222 chips on it.. but this time it just stays on... no ocilation

:-(, I'm heading to bed soon and busy tomorrow.  c4757p's got much more experience than I, but if you're still having trouble by wed, I'll board one up and link a video here.  It really should just work.

If you're interested, you can also make a square wave generator out of a single opamp, might give you inspiration for further inverter design/experiments.

Cheers

[c4757p]

Can you take another picture? I can pretty much guarantee you that the circuit (at least, the oscillator part) will work fine, so either you have it hooked up wrong or the transistors are faulty.

If you're interested, you can also make a square wave generator out of a single opamp, might give you inspiration for further inverter design/experiments.

The beauty of using a transistor multivibrator is that you get both a 0° and 180° output for free, making it easy to get true AC instead of just pulsed DC. Hard to beat a circuit that gives you exactly what you need at the cost of two transistors.

[madshaman]

The beauty of using a transistor multivibrator is that you get both a 0° and 180° output for free, making it easy to get true AC instead of just pulsed DC. Hard to beat a circuit that gives you exactly what you need at the cost of two transistors.

Agree, but figured it was a nice start to linking in more opamp circuits to make different waveforms etc., get used to buffering outputs so you don't destabilise the input circuit etc.

@Nickk2057 you're in good hands with c4757, my advice though: save your pennies, beg borrow or steal (well don't do that) a scope, any scope (okay maybe not usb scope, you don't want that for your first scope), for the stuff you're interested in it's utterly vital and you'll never look back.  Nice work keeping at it!!!

Edit: if someone even offers you a USB scope for free, throw it at them and say: "I don't want that for my first scope!"

[Nickk2057]

ok.... i checked the transistors hooked up to an LED to see if it will power it on and it did.. so the transistors are fine for the most part...... if one of you all have an insite on it let me know.. so i can try to fix it to see if i cna get it up and running.... also i am having the mosfets hooked up to an arduino with a code to set the frequency.. and it works just fine.. tho there is a hum when its on no load.. but it works good on it

[Nickk2057]

here is the video of it...

[Nickk2057]

and excuse my speech on there too XD

[madshaman]

and excuse my speech on there too XD

Cool :-).  With three opamps you can also do PWM, I'll stop pushing opamps now ;-).  Get a scope!  Throw USB scopes back at people or sell for beer money (or coca cola, sometimes it's much better).  Off to bed am I.  Keep at it!

[Nickk2057]

thank you madshaman.. you were very helpful... and if you can... would you try it too to see if it works for you?... it be better if there are two heads then one... with that it will help me out greatly...  or even three for that matter...

[c4757p]

Give me a minute, I'll throw the circuit together here and see if I have any issues with it.

[Nickk2057]

okay... thank you

[c4757p]

Works fine for me.

[Nickk2057]

now what kind of caps are those.. cause i was using the ones that is used for to use on a tweeter of a speaker on that circuit... the 2.2uf type

and plus 76 Hz is kinda high tho

[c4757p]

They are Wun Hung Lo-brand electrolytics, 2.2uF. 76 Hz is reasonable for the tolerances given (those resistors are 1%, but the capacitors are something on the order of holy-shit%). If you need 60 Hz accurately, add a trimmer, or even use a crystal.

Edit: The caps clock in at 2.1uF and 2.2uF, so pretty much perfect. However, those values actually give a frequency of about 70 Hz, so 76 is close. It's the circuit design that's off, not the build.

[Nickk2057]

trimmer? meaning like a pot?

[c4757p]

Yup. You can replace part of the 4.7k with a pot. (Of course, since you're probably only building one of these, it would make more sense to just sub in a different resistor or capacitor value.) Or just settle for the 76 Hz.

[Nickk2057]

UGH!! it still won't work... even had it hooked up in a analog port on my computer with Zeloscope to read it but it just jumps and falls back to zero when i hook up the battery to it.

[c4757p]

I really have no idea what's going on with it! Try using different transistors. I was going to suggest that a connection was loose (I actually was having problems with that myself, those 680 ohm resistors have thin-as-hell leads...), but I see you've soldered it all (probably overkill).

Also - how exactly are you hooking this up to your computer? If there's no attenuator somebody is going to be unhappy with that 12V waveform. A single resistor is not an attenuator. Use a real voltage divider with relatively high-value resistors (at least 100k total).

And goddammit Google Chrome spell check, "attenuator" is too a word!

[Nickk2057]

hold on and i will hook up my arduino to it and it will show it...