@Keno – “Yes, heart of the problem is % “the changing of voltage” Right. So stop beating around the bush and tell us what the voltages. Hi, Elektor – I might call- circuit is not bad. Couple of minor modifications made here. Check this out. Item, Type, Manufacturer, Date. Elektor – July/August , Magazine, Elektor – November , Magazine, Unknown. Elektor – October , Magazine.
|Published (Last):||25 August 2007|
|PDF File Size:||15.50 Mb|
|ePub File Size:||7.43 Mb|
|Price:||Free* [*Free Regsitration Required]|
Alternate method is the step load Q or ringing response to determine stability margin. Warning this will affect loop bandwidth and step load response time. Instability due to the use of lower voltage supply in the Post eleotor a guest Name. Home Questions Tags Users Unanswered.
Increase the value of C4 until stable eoektor to 10x. Paulo Morgado – favorite favorite favorite favorite favorite – February 27, Subject: Not all of the information is current. Any challenge with failures is a good experience to learn. You can show this on your thesis to demonstrate real world issues.
A common issue is the thru hole lead inductance of cap and ground connections can cause phase shift and if not compensated properly will oscillate.
Isolate the problem section, determine the error, and fix it. Thus something is loading it. Did you measure phase margin from step load? I would tell you Check some things: Then the voltage changes slowly from 3V-5V. And if the voltages are changing, then isolate the section by removing the 3 base drive components R9, D4 and D5and find out why the is acting up.
Forgive me if I wrote some nonsense I do not speak English and I use google translator. If the first PCB works without this compensation then why would the not-working one need it. And if I connect load on the output the voltage slowly descends till 0V everything seems like there should be a capacitor making these problems I changed Op-amp, LM and a few capacitors every of them but smoothing capacitor – my professor said that it wouldn’t be making such problems.
Keno 1 9 Stop beating around the bush with generalities.
Elektor – – Computing History
This old design uses external compensation for 2nd order effects which in closed loop Op Amps causes loss of phase margin and can cause oscillation is no margin. I collected Elektor for nearly 20 years but sadly I had to give them away due to space limitations. EEsince’75 – For what it’s worth, I’m surprised as well. High ESR of electrolytic capacitors did you check this?
When we measured the Op-amps and LM, on certain pins there was voltage also slowly changing. Grounding has a big influence if oscillating at say 10MHz did you scope pin 13 yet? I managed to solve it, elktor defect was because I replaced the original transistors T Just what I was waiting for – brilliant!
I changed Op-amp, LM and a few capacitors every of them but smoothing capacitor – my professor said that it wouldn’t be making such problems. I am grateful if you can help as I used google to translate this message before. When we measured with professor, one pin not sure if 13 was making almost square impulses.
Advanced embedding details, examples, and help! Search the history of over billion web pages on the Internet. Now it works perfectly.
And are you sure the – supply is properly isolated? Topics ElektorMagazineCollection. Me and my mentor professor did all kinds of measuring on the not-working PSU – measuring connections, short circuit possibilities, voltage measurement on specified components and with oscilloscope too.
This is also my final school project. Sign up using Facebook.
File:PSU-ElektorARTICLEJPG – emboxit
Elektor Magazine Item Preview. When I raise the voltage setting the voltage goes up to 32Vdc when it should go up to 47Vdc, when I reduce P1 the voltage goes up and the potentiometer works upside down min: Most likely solder connection errors. And if I connect load on the output the voltage slowly descends till 0V everything seems like there should be a capacitor making these problems.
Sign up using Email and Password. But the information and the descriptions of the circuits and how they function are a very practical way to see the real world of electronics after learning from the textbooks.
I saw through your measurements that some voltages are way out of the way