Hello,
I built Mr. Carlson’s Curve tracer a few months ago and it seemed to be working well on the bench. I finally got around to building an enclosure for it and getting the project completed. After getting everything mounted and all the connections soldered to the banana jack connecters I ran through the alignment procedure again. This time I get a beautiful sine wave after adjusting the pot for clipping with the H input connected. The issue is that my sine wave is measuring about 22-24v PP. at the same time the Meter that is connected is reading around 10.6v. If I put a resistor on the probe I do see the angle form and I see the diode breakdown curve and I do see a circle waveform when I connect a cap if I adjust the volts per division far enough. The other thing I noticed is nothing really happens when I flip the switch, The waveform blinks like the connection was broken for a millisecond but that’s all. I used the scopes calibration waveform .5vPP and that all measures fine. I am in the process of checking connections starting with the switch and moving through the schematic.
If anyone has any suggestions on something I can check I would appreciate it. It’s kind of hard to ohm everything out now that its mounted in a case but I’m working through it.
Thanks,
-Jeff
Hi, from what you.ve described so far it looks to me that your curve tracer actually works as designed and that there is nothing to be fixed to it. The problem is knowledge. Let me explain. The sinewave level you have measured as around 24V is Peak to Peak meaning it swings from positive rail to negative rail but the voltage you have measured at the output connections (designated for a Voltmeter to be connected to) is DC voltage only. meaning Peak voltage only:
Thank you very much, I will watch them again. It’s been a few months since I viewed them. I seem to remember it functioning differently. I just went back and looked at the alignment procedure printout and it clearly states the meter should match “The Peak” reading on the scope. feeling pretty stupid about now. I guess the bright side is the curve tracer is working well after all. Thanks again for replying to my question. -Jeff
@slug54 Well, I’d say don’t worry about being stupid, cos you’re not. Everybody can make wrong assumptions at some point only to review it after it and realise the contrary but hey, we are all here to ask questions and learn from each others experiences as well as mistakes so…. no question is stupid at all. Who doesn’t make mistakes ? I know I surely do from time to time. 😏. But, someone at some point reading the posts can still greatly learn from it. I’m glad I could be of help. So, peace of mind, no worries at all. 😉
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