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Recent content by fadGadget

  1. F

    Temperature compensating a transistor?

    Tested it. Improved the result a tiny bit but not enough I'm afraid. Would it be possible to implement a current mirror at the transistor or does the topology complicate things too much here, you think?
  2. F

    Temperature compensating a transistor?

    Hey Kris, nice to see you couldn't resist to test the circuit anyway :) Still, it seems to perform better IRL than in the simulation. Apart from the temp issues, that is. And hey Adam and Ratch! Nice to have your input, got to breadboard your suggestions right away! Thanks
  3. F

    Temperature compensating a transistor?

    Well, I kind of suspected that, guess I'll be looking for a FET solution in that case. Thanks for taking your time anyway.
  4. F

    Temperature compensating a transistor?

    Hi Kris, 1. Approx. 0.45 up to 2.45 V if I remember it correctly. 2. Yepp, higher voltage = higher frequency 3. No, got smaller caps on now, 33nF and 3.3uF. 4. Well, I run it directly from a bench DC power supply. I've tested with 12 and 15v too. Measurements done at 9 volts +/- . 5. Works with...
  5. F

    Temperature compensating a transistor?

    Fyi: I'm a noob in electronics so I won't argue against what you are saying here above, still, I've built oscillators before based on different chips like XR2206,2209 and ICL8038 and found they're really not that linear one might expect. This one covers 20Hz - 20Khz easily with a perfect shape...
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    Temperature compensating a transistor?

    Hi, and thanks for your quick reply! I run the opamps from +/- 9 volts and get a perfect falling ramp. Strangely, I can reverse the transistor and still get a good looking wave. The pot is used for controlling of the frequency. The problem as mentioned before is that the transistor is too...
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    Temperature compensating a transistor?

    Yes, you are absolutely right. :oops: Guess I rushed the schematic together, tried to simplify things too and it turned out a mess, sorry for that... Here's a new one and this is really what's on my breadboard right now. One can run it on 9 -15 v with just a few adjustments.
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    Temperature compensating a transistor?

    Hello, This is my 1:st post here :). Wondering if anyone knows how to temperature compensate a single transistor? I have this simple Schmitt trigger vco and control the frequency via the base on the bjt npn (see below). I get a nice waveform from it but the transistor is extremely temp...
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