@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.
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When we measured with professor, one pin not sure if 13 was making almost square impulses. I found your data useful but not in the presented form, so I imported into a spreadsheet to align the results in two columns and then imported the images from the datasheet PDF.
Did you measure phase margin from step load? Tony EE rocketscientist 62k 2 21 Since you have not seen fit to let us know exactly what is going on, I’ll guess. An important addition to the Archive An important addition to the Archive. EEsince’75 – For what it’s worth, I’m elektof as well.
Now it works perfectly.
Sign up or log in Sign up using Google. Sign up using Facebook. Thanks for the effort it took to elektr this all together. All of these measurements were measured to the common GND of circuit in that part of circuit stabilizer stage. Alternate method is the step load Q or ringing response to determine stability margin.
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I am also surprised you accepted this an answer. Grounding 19822 a big influence if oscillating at say 10MHz did you scope pin 13 yet?
Instability due to the use of lower voltage supply in the 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.
WhatRoughBeast 49k 2 28 Mine still has trouble adjusting the voltage.
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What we found out is next – after turning on the PSU, the output voltage rises to certain level depends of voltage potentiometer and than starts to slowly descending til 3V. Warning this will affect loop bandwidth and step load response time.
Be sure to comment on finding the defect. Listen to what IgnacioVazquez-Abrams said too. If the first PCB works without this compensation then why would the not-working 19822 need it. 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.
Glad your circuit works.
Since you have a working one, did you compare the non-working one to the working one? When we measured the Op-amps and LM, on certain pins there was voltage also slowly changing. Isolate the problem section, determine the error, and fix it.
Forgive me if I wrote some nonsense I do not speak English and I use google translator. I collected Elektor for nearly 20 years but sadly I had to give them away due to space limitations. Just what I was waiting for – brilliant! Post as a guest Name. How about contact of the heat sinks?
T5 with higher gain ones and this elekktor instability to the circuit.