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    Function Generator + LCD (Design Idea)

    Nobody should be without a function generator. I know there are chips that you can use, but it is still good to learn how these things work. The stand alone chips have very limited output power and the lower spec parts may have quite high sine wave distortion. Here is a design I did using one...
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    Transformer design in SMPS

    Power in SMPS will be mainly limited by: Effective core area Switching frequency Core loss at switching frequency vs peak flux swing Copper loss Switching losses of the active device Rectifier losses
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    Crystal examiner

    Just to explain the concept of negative resistance. If we take the transistor circuit without the crystal connected and use a NWA to look at the real part of the input impedance (red) and available gain (blue), we can see that our values generate the plots as shown. We can see that the red...
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    microwave oven service manual

    Here is a conventional diagram http://www.eserviceinfo.com/downloadsm/27009/Daewoo_KOR-180A2A,%20KOR-181G2A,%20KOR-181H2A.html Also http://www.repairfaq.org/sam/micfaq.htm Many modern microwave ovens now use a HF, high voltage switch mode PSU
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    measure power in reactance component

    You need a varmeter that measures the the product effective [(Voltage x Current) x Sin (angle between V and I)] . Reading will only obtained when V and I have a a certain phase difference. Readings for 0 deg and 180 degree phase difference will read zero.
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    Oxygen Sensor Tester (Design Idea)

    Oxygen senser feedback is disabled while engine is still cold or full-throttle operation. Max power requires a rich mixture.
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    Oxygen Sensor Tester (Design Idea)

    Recently a friend
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    Crystal examiner

    Thank you for your kind remarks, but actually I am O+ who loves EE in a mainly <-O world.  ;)
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    Crystal examiner

    To get the values of LS,CS, RS and Co Measure the points Fs and Fp very accurately. Use narrow span on NWA Measure holder capacitance Co with LCR meter at low test frequency (1-5kHz) Then: CS = Co{(Fp/Fs)^2 -1} LS = 1/{[(2*pi*Fs)^2]*CS} RS = {2*(NWA impedance)*[10^(insertion losses/20)-1]}...
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    Crystal examiner

    (a) That is the same as: SQRT(RS* DC gain) = SQRT(50 * 100) = about 70 (correct me) yes (b) What this value? I mean what does that mean? Get ratio for loop gain vs C1, C2 values needed to be able to oscillate with given RS Now lets discuss about some relevant points : (1)The Crystal examiner...
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    Crystal examiner

    (a)It was difficult to obtain any information from the seller in my country. How can measure these parameters by network analyzer? I will provide a method for you later. Your network analyzer should be able to accurately measure Fs and Fp (b) Do you not see that the value of Ls = 0.08H is very...
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    motion sensor power supply problem

    I think it should trace out to be something like this. The 24VDC is further regulated down by another zener on the sensor pcb by the looks of it. You should be able to apply your 24VDC at the point indicated after removing Q1, or 24VAC  by removing C4 and making R3 small enough or short out...
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    Voltage Controlled Oscillators & FM demodulator

    Mathematical analysis of the usual Foster-Seeley and ratio detectors reveal a problem. To have very good reproduction of the modulating signal the split secondary winding should have equal properties. This is very difficult, if not almost impossible to achieve in real life. The slightest...
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    How to divide Asynchronous data in 2 parts

    One way to this is to use a technique called least-squares compression. It compresses the data in a time frame to allowed it to be read out at a lower data rate. Search Google for more information. This is often used in simulation programs to speed up processing and optimization of results.
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    Silly transistor question, Voltage to the base

    The collector Vceo implies the breakdown c-e rating with the base connection open. Transistors are hardly ever used like this, as normal operation always requires the b-c junction to be reverse biased. With reverse bias the c-e breakdown rating can be as high as 3 x Vceo. Designers like to use...
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    Crystal examiner

    LESSON: COLPITTS CRYSTAL OSC DESIGN, AN920
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    Crystal examiner

    I will respond more complete when I have time, but here is some idea of minimum parrallel (load resistances) across crystal that will still allow circuit to oscillate. Freq MHz       Res value 20                  3k 10                  4k 1                    27k 0.5                 370k...
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    Voltage Controlled Oscillators & FM demodulator

    Most single stage varactor RF VCO's will also suffer from modulation sensitivity. That is you need to apply more modulation level for the same required deviation as you increase the tuning voltage (higher frequency) to the VCO. Example: you will need much more modulation for the same loudness...
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    Crystal examiner

    Plots shows happy and more happy circuit values. First plot shows osc struggling to start because of low loop gain. This circuit will not work with very low value crystals like 32kHz watch crystals as the crystal will be loaded too much. You need an oscillator circuit with a FET input for this...
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    Crystal examiner

    The caps will set the feedback ratio. If this ratio is too small (as in this case) the circuit will not oscillate as the loop-gain is less than 1. Try swapping the 2 caps around then it should work. As you go higher in frequency the cap values should be reduced. 20 MHz crystal would require...
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