I wanted to modulate ? DC with AC or vice versa
So I got a 1500 ohm resistor and put some AC across it through a VARIAC and transformer
Got a nice little sin wave
Next I thought ok cool now it's time to add some DC and I can make the sin wave go up and down
Seems I forgot that a DC power supply will ground out AC :grr
IMG_20260808_130150730 (1).jpg
So I'm gonna have to think about this one for a while xP
I think one thing I'm noticing is maybe have a small miniscule AC and a large(r) DC
Hmm oh yeah now I'm starting to recall seeing something like a diode clamping circuit
Might be time to check it out :tu:
This worked pretty good and was easy to set up
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I couldn't get much separation :grr
Sorry for the strobe light display
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So starting changing out different capacitors and resistors trying to achieve lift off for channel two but despite my efforts they stayed close and tied up comingled like two fighters that the referee is constantly trying to separate :grr
The point of this I'm still not getting the AC vs DC thing so I'm trying to take a look at various aspects
This will be a good opportunity to maybe learn a few things
Put the DC supply in series, between the bottom end of TX secondary and ground.
Your drawing shows it in parallel, across the TX secondary.
Man.... :lmao: :dbtu:
I have to say I'm totally floored :tu:
Started hooking it up
I can't believe what I'm seeing
PACO's not even turned on yet and the AC is traveling through its neutral and the 22k resistor
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Now I'm scared to turn PACO on :'( :lmao:
What neutral, what 22K? You are scaring me a bit now so maybe stop til you can draw out what you are doing.
Dude IT WORKS :dbtu:
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At first it "didn't work" because I had the scope on AC but then I switched it and
LIFT OFF
sorry about the flickering scope display it literally drives me BANANAS
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R1 value (22k) randomly selected :loco
Great. Just to clarify, what concerned me was the use of the word 'neutral'. That is a very specific term which is only used for one side of the mains AC line. As soon as you use that word, it raises concerns about electrocution as it is one side of the 'live' AC coming out of the wall.
So I think you probably meant the (-) or 'common' terminal of PACO. 'Common' is the best word to use for a reference point that is not necessarily tied to ground. Like the one you just made that is floating on DC.
Holy cow :lmao: wow ok
Yeah I can understand your concern that does sound pretty messed up like I connected it to the power cord xP
Btw this raggedy a$$ house is all jacked up
I don't think any of the three prong outlets are actually grounded :grr
One time I looked it up and I think it said measure AC from the ground socket and the neutral/common
If you see a difference there's a problem :grr
Btw I'm still in awe that that worked :dbtu:
It's gonna be a while me trying to figure that out :grr :lmao:
Reminds me of the time I was in a pickle 🥒 because I need negative voltage on a pin of a DIP I was freaked out and you were like "dude..what's the problem?!?!" 8| :loco xP
So I went back and looked at my signal generator remembering that it has a DC offset control
I set everything up using that and like clockwork using the DC offset I was easily able to make "the AC go up and down"
(Provided I had my scope on DC coupling and also the DC movement was kinda crappy only about 5V each way)
I remembered having trouble with this and sure enough I was told I had the scope coupling wrong
https://www.ssguitar.com/index.php?topic=5281.msg41307#msg41307
Back then those settings didn't mean too much even if I learned what they did it wasn't the same as experiencing it :tu:
Nor did I imagine like now that probably when your scope is on AC coupling it runs the signal through some capacitors and the DC can't make it through (ya think)
Which is another thing oh yeah noobs read "DC can't go through capacitors"
So yeah we write that down and remember it and swear in blood yeah it's a rule :trouble "
But until I had real stuff on the bench it was just a bunch of concepts that well these other guys they know all this stuff and so should I
So now when I see the switch on the bottom of the scope probe BNC it actually means something :grr :lmao: :dbtu:
But hey all good in the hood :dbtu: I'm gonna be able to set some more stuff up and then see what I get with a meter set to AC then DC and then on the scope and get this sorted out :dbtu:
Another thing yeah the rich get richer it all goes hand in hand because maybe now I could take the lid off my signal generator and see a 741 and a DC source and so on and possibly take notice of the different sections of the terrain xP
I would never take the lid off my scope but maybe look at a schematic and see the inputs and where the capacitors are for the AC coupling xP
(I know what you're thinking.....yeah brah that's awesome only took ya three years to figure it out)