I am using a switching supply, although its a high quality one. The 10 nF cap did not change a thing.
[QUOTE=alexaz;42894338]I am using a switching supply, although its a high quality one. The 10 nF cap did not change a thing.[/QUOTE]
A high quality supply still has noise that can disturb your circuit.
[QUOTE=alexaz;42894338]I am using a switching supply, although its a high quality one. The 10 nF cap did not change a thing.[/QUOTE]
try using a battery as the power supply.
[QUOTE=Van-man;42894535]try using a battery as the power supply.[/QUOTE]
Did try it, no change.
[QUOTE=alexaz;42893383]So i'v been trying to build the god damn linear regulator once more.
[img]http://i.imgur.com/6D8a4II.png[/img]
[/QUOTE]
I do believe your op-amp isn't providing enough current to the npn to properly bias the TIP32, thus not allowing enough current to flow into the regulation to hold the 5V.
You may have a low-beta NPN, could you test for your 3904's beta? You may just have to try another (3904's are a rather crappy transistor in my opinion for [URL="http://www.robotroom.com/BipolarHBridge4.html"]alot[/URL] of reasons)
[QUOTE=alexaz;42894688]Did try it, no change.[/QUOTE]
After some experimenting I've come to the conclusion that the PNP pass transistor and output capacitor are the source of your trouble (no wonder people call LDOs unstable), I'm not entirely sure of the precise cause but it seems the PNP is unable to turn on or off very quickly, as a result the output overshoots and undershoots causing a oscillatory effect, the quickest solution I could think of is to place a resistor between the base of the PNP and the collector, this will affect the DC accuracy but it will stop the oscillation.
I'll look into it further.
The layout actually is not that far off from a Sziklai pair (complementary pair) which would explain the slow operation thanks to Mr. Miller capacitance.
[QUOTE=LoneWolf_Recon;42895338]I do believe your op-amp isn't providing enough current to the npn to properly bias the TIP32, thus not allowing enough current to flow into the regulation to hold the 5V.[/quote]
I agree the base current is too low for trying to output any more than 100mA, however it would not cause such instability.
So if I have a op-amp with a Operating Voltage limit of ±18V, doesn't that mean it can maximum handle +18V and -18V with the GND in-between?
[QUOTE=Van-man;42896026]So if I have a op-amp with a Operating Voltage limit of ±18V, doesn't that mean it can maximum handle +18V and -18V with the GND in-between?[/QUOTE]
Yes.
I officially fucking hate Semiconductors. I just wasted the last hour on a question, wondering why my value for kT/q=Vt wasn't ~26mV at room temp, after I found out that's what it's supposed to be. I finally found out it's because I'm using the wrong value for k, instead of using 8.62x10^-5 eV/K, I'm supposed to use 1.38x10^-23 J/K, else I get 1.62x10^17. This is fucking obnoxious, I hate it, and it makes me feel retarded.
Thats why you always do unit arithmetic when doing any kind of physical calculation.
Electron-volts to joules are kinda what pounds are to kilograms.
What's the best, simplest and cheapest way to generate a 40 to 50 kilohertz triangle wave signal?
Google opamp triangle wave generator.
[QUOTE=DrDevil;42903124]Google opamp triangle wave generator.[/QUOTE]
Tried those, only truly useful info i got out of those were that the op-amp's used must have a high slew rate.
[QUOTE=Van-man;42904084]Tried those, only truly useful info i got out of those were that the op-amp's used must have a high slew rate.[/QUOTE]
Not necessarily, at 40-50kHz most op-amps will do fine, alternatively use a 555 timer or if you're feeling adventurous transistors.
[QUOTE=Chryseus;42905053]Not necessarily, at 40-50kHz most op-amps will do fine, alternatively use a 555 timer or if you're feeling adventurous transistors.[/QUOTE]
I doubt those 4558DD op-amps I've nicked from a small amplifier from early 90's are capable though
[QUOTE=Van-man;42905183]I doubt those 4558DD op-amps I've nicked from a small amplifier from early 90's are capable though[/QUOTE]
Slew rate: 1V/us
Sounds good enough to me.
Ive been looking at magnetic amplifiers and saturatable reactors, really interesting things!
have a pdf! :D
[url]http://www.tubebooks.org/Books/mag_amp.pdf[/url]
[QUOTE]Slew rate: 1V/us
I doubt those 4558DD op-amps I've nicked from a small amplifier from early 90's are capable though[/QUOTE]
Any more than 20uV will start to slew at 50Khz, you'll be fine. A mV or so would do the trick.
Problem is that all the formulas I've tried either doesn't straight out work, or ends up spitting out a capacitor value higher than what I have in stock.
Currently only have 2pF to 100pF ceramic capacitors for this.
[QUOTE=Van-man;42906856]Problem is that all the formulas I've tried either doesn't straight out work, or ends up spitting out a capacitor value higher than what I have in stock.
Currently only have 2pF to 100pF ceramic capacitors for this.[/QUOTE]
Decreased resistance will allow for higher value capacitors.
Almost all the parts for the programmer FINALLY came in (I fucked up and only ordered one two pole toggle when I needed two) but regardless I was finally able to glue on the overlay and attach everything. It LOOKS like a real programmer now!
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0433.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0294.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0296-1.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0295.jpg[/IMG]
Now all that remains is to solder the assload of wires that will make it all work....
Anyone got any suggestions on how to store a large number of IC's ? I've got tons of different ones from standard 7400 and 4000 logic to application specific chips like CRT RGB drivers.
Put them in those antistatic foam thingies and then stack them in a sortiment box.
Made my first bridge rectifier today. *proud*
Behold, my latest ebay win, can you guess how much i paid for all of this?
So many IC's i had a NORgasm:
[URL=http://imgur.com/FlzpltZ][IMG]http://i.imgur.com/FlzpltZl.jpg[/IMG][/URL]
Enough capacitors to delay my next restock time for at least 3 life times:
[URL=http://imgur.com/SSnfiyu][IMG]http://i.imgur.com/SSnfiyul.jpg[/IMG][/URL]
Ohm my god, so many resistors (the box is as deep as it is wide):
[URL=http://imgur.com/YCAhoe0][IMG]http://i.imgur.com/YCAhoe0l.jpg[/IMG][/URL]
Enough optoelectronic parts to light:
[URL=http://imgur.com/eykGRyH][IMG]http://i.imgur.com/eykGRyHl.jpg[/IMG][/URL]
Zenners, thyristors, transistors and temperature sensors:
[URL=http://imgur.com/syYhyqR][IMG]http://i.imgur.com/syYhyqRl.jpg[/IMG][/URL]
Enough relays and switches to control the national grid:
[URL=http://imgur.com/4H7WpiQ][IMG]http://i.imgur.com/4H7WpiQl.jpg[/IMG][/URL]
This is why ebay is awesome.
Let me guess, you paid ~$200USD. Also, who was the Ebay user you bought it from? Do they do more lots like this?
[QUOTE=LoneWolf_Recon;42918322]Let me guess, you paid ~$200USD. Also, who was the Ebay user you bought it from? Do they do more lots like this?[/QUOTE]
It was actually from a guy who retired from the business, i estimate all this stuff, if i brought it from RS or farnell would likely come out in the £1000s
This is the entire contents:
[url]https://drive.google.com/file/d/1hyuP5R8Jg602iRfCVRxxcwmDgB69TAmIvqsl4lp8QPyVnILvpqakJGVV2Wkt/edit?usp=sharing[/url]
You lucky son of a bitch.
[QUOTE=Nightrazr;42918690]You lucky son of a bitch.[/QUOTE]
heres a picture of the box im storing it in, a biro next to it:
[URL=http://imgur.com/FWWTxOu][IMG]http://i.imgur.com/FWWTxOul.jpg[/IMG][/URL]
Also, anyone in the UK want a whole load of buzzers, il give a entire bag of them for £15 + P&P (around 150 pcs of them)
Info:
PC mount White 23mm dia. 7mm high pin 4mm
...I need to browse ebay more.
Any plans on opening a store :P
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