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    microwave oven service manual

    http://www.gallawa.com/microtech/magnetron.html
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    The Oscilator projects

    Use the darlington I used or just a common bipolar like a 2N3904 or 2N4401. Power darlington's internal structure is different with low value resistors to help speed up switching time.
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    Electronic ignition

    You may find old issues through your local library. Here are a few listed on this page. http://www.nleindex.com/index.php?pID=HTDI&sID=BrowseIndex&tID=E/99
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    Small FM Transmitter 1965!

    This transmitter dates back from a 1965 electronics magazine. Circuit looks very much the same as many circuits on the web today. Some things never change.
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    Motor to drive a metal disc

    DC motors have a lot of pull-out torque. Using a gear box enhances that.
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    Motor to drive a metal disc

    You will have to calculate the moment of inertia. You need the radius of your disc. M.O.I = (mass x radius^2)/2 From here you can calculate the required torque requirement. It will help a lot if you know: 1) The load torque 2) Required rotation speed (rpm) 3) Time allowed to get up to speed (sec)
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    DS1869-10

    http://pdfserv.maxim-ic.com/en/ds/DS1869.pdf
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    Energy saving device - can they work?

    In a recent article it was calculated that the savings for an average household would be only 0.1% of the total monthly electric bill. For industrial applications with lots of motors it will pay over time.
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    The Oscilator projects

    I don't know about power darlingtons. I implemented the small signal darlington in a design in this thread. http://www.electronics-lab.com/forum/index.php?topic=11442.msg62103;topicseen#new
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    The Oscilator projects

    Ok, I was wrong. They do work, and quite well. Just hooked up one here in the lab.
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    The Oscilator projects

    I have not tried darlington's but due to their structure they will be very much slower  in switching if they switch in this mode at all. I have a feeling they won't work.
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    The Oscilator projects

    Changing the value of the resistor will vary the frequency. This type of oscillator works because of a negative resistance region created at the reverse breakdown potential level. You should not make the resistor too low and damage the transistor. I have done some experiments on this type of...
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    Transformer design in SMPS

    Typical Ku factors for standard converters: Forward                  0.4 Full and 1/2 bridge 0.4 Push Pull w CT        0.4 ~ 0.5 (0.5 for the single ended secondary output) This sounds low but due to the shape of standard round copper wire, if you do the math only about 78% of the available...
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    Transistor Switch???

    This shows the potential problem(1) of the circuit. In normal operation with a low load impedance there would be no problems. It is always good to be aware of such problems when used in certain applications. Example: If the output is sensed by another very high impedance instrument like in...
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    Transistor Switch???

    The circuits won't work with a normal opamp and is meant to use a open collector comparator. The following diagrams show one of the problems I stated earlier The first two diagrams show the circuit in both conditions. ( I only left the switches in their respective states for clarity). It can...
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    Whats wrong it wont work!

    You only have about 2.5V on the gate to try and turn on the MOSFET
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    Transistor Switch???

    Two problems. 1) It the first circuit, the PNP transistor will never be completely off. This may not be a serious problem, but can cause problems depending how this circuit will be used. This can be fixed by adding a 10k resistor between b-e to cancel the leakage current through the diode. 2)...
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    Transformer design in SMPS

    Because in practical situations only about 40% of the core window area is filled with copper. The rest is used up by the bobbin and insulation. Winding packing factor is normally considered a constant with, Ku ~ 0.4
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    Function Generator + LCD (Design Idea)

    Here is the Bill-Of-Material. I also found these free evaluation programs that uses your PC sound card as a distortion analyzer. This may help you to adjust the triangle to sine stage for minimum distortion if you don't have access to a distortion meter...
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    Function Generator + LCD (Design Idea)

    I thought the generator should have some form of frequency readout to make it more user friendly. Also many members will not have a frequency counter making it difficult to set the frequency. Driving LCD's is quite easy, so this was the obvious way to do this. I used a PIC16F628A for this...
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