Recent content by AN920

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    Feed back amplifiers

    Do you mean, (serie-shunt,shunt-shunt,series-series and shunt-series)? http://www.ece.mtu.edu/faculty/goel/EE-4232/Feedback.pdf http://www.scribd.com/doc/92675/EE3102-Experiment-1
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    Micro FM TX (Micromitter)

    Sarma, noted and done. :)
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    Micro FM TX (Micromitter)

    Here are some pictures showing the 100 kHz noise pulses into the VCO tuning line. In the first picture it is not easy to spot the problem. The scale is 1mV/div The next picture shows the pulses after I averaged it 64 times. The 100 kHz pulses can be clearly seen. These pulses are very narrow...
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    protection circuitry for IGBTs in inverter

    You need to provide more information 1) Which IGBT's are you using? 2) What size motor are you driving? 3) What type of load. Pump, fan etc. Under which conditions do they fail?
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    Micro FM TX (Micromitter)

    Hi Sarma, No, that won't help as I will show below. If you look at the first plot, you will see that with the 47nF connected between the base-collector of the MPSA13 the gain at 100 KHz is about 6.5dB. This is the problem I suspected. In the second plot, by moving the 47nF to the base-emitter...
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    Micro FM TX (Micromitter)

    A good friend of mine in Australia bought one of these kits. He was having some problems getting it to work properly. He posted it to me to look at. Here are my findings and some modifications I did. I will address it point by point: 1) Move this cap closer to pin 12. The PLL Vcc is very...
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    Function Generator + LCD (Design Idea)

    Someone suggested the faster LT1353 to extend the operation to over 100 KHz. I will look into this. The PIC clock will have to be much faster for the counter.
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    0-30 Vdc Stabilized Power Supply

    The current probe or current transformer method was suggested by Dr. Middlebrook long ago. Every injection point has its pros and cons. I think where a loop is very marginally stable various methods may make a small difference, but where it shows obvious instability it won't make much of a...
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    RC mini Helicopter

    When I started to fly RC planes long ago (I don't anymore), I started with a STIK-40 with a tuned pipe. Radios with 4-6 channels were expensive. There were many beginners who had 2-chan radios. When the local club found out that I was into electronics, everyone wanted me to repair and check...
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    0-30 Vdc Stabilized Power Supply

    If you are referring to the bode plots of the PSU loop stability, that was injected with a current transformer inserted into the feedback path. I could have injected in the error amp's own feedback path as preferred by some people. In this case I don't think it will make much difference.
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    Commodore 64 repairing gone forgotten?

    Hi Omni, I used to have a Quad tube amp that sounded great. Only 15W rms but outperformed the 50 W transistor amps. Today I am sorry that I traded it for an old RF Motorola signal generator back in high school.
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    0-30 Vdc Stabilized Power Supply

    Future Electronics have 10,000 + in stock at $0.18 ea. FC shows it is still in full production http://www.fairchildsemi.com/pf/MJ/MJE180.html
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    0-30 Vdc Stabilized Power Supply

    I think I found a possible replacement. Look at the MJE180 from Fairchild. http://www.fairchildsemi.com/ds/MJ/MJE182.pdf Good, Ft (50 MHz), gain (50 min) and Ic (3A) Initial simulations look very good. Very stable with low ESR values and very fast loop load-step response (200nS). I will...
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    0-30 Vdc Stabilized Power Supply

    That was the intention in the original design with a much better transistor. The whole picture changed. The situation will be the most problematic during load switching of high currents. It will be the worst at high output voltage settings and will get worse with lower ESR values. As-is, a 10uF...
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    Negative resistance experiment

    Sorry, Walid I will respond more in detail when I have more time.
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