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    Ferrite core transformer design

    Yes... in SMPS.
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    [b]Questions regarding Switched-Mode Power Supply[/b]

    Only in a ZCS or ZVS supply... the other topologies don't have that luxury. In terms of SMPS, the number one thing to get a good understanding of is the concept of Pulse Width Modulation (PWM)... a concept you might want to include in the "Technical Articles" that pertain to DC-DC's on your...
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    [b]Questions regarding Switched-Mode Power Supply[/b]

    That is not correct. Inductors have resistance (the wire itself) and capacitors have ESR both of which will and do dissipate power (heat).
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    DC Motor help required

    You could try windshield wiper motors.
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    [b]Questions regarding Switched-Mode Power Supply[/b]

    What???
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    MOSFET VGS

    Not true... I use small MOSFET's (Vishay) that have a  Vgs of 1.2V... I wouldn't consider that high. No... re-read and UNDERSTAND what Hero999 just said!!!!! If you are really serious when you say that,  I'd recommend you get yourself a good book on semiconductor physics read that, then...
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    [b]Questions regarding Switched-Mode Power Supply[/b]

    The power density of switchers is quite high... for example my (work) bench supplies are Xantrex a XHR 100- 10 (100V @ 10A) and a XHR 40 25 (40V @ 25A). Both are 1 KW supplies and measure ~3"x8.5"x16". In a linear supply of the same power, the transformer would probably bigger than that by...
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    Pi filter for impedance matching

    This is a "second order" circuit. You took a bode plot over a frequency range. Things are going to change over frequency. Have you solved the differential equation for this circuit to find the poles and zeros? It's also what is called a "passive circuit"... so, unless you hit a resonant...
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    MOSFETS in parallel

    That transistor has absolutely nothing to do with the biasing of the MOSFET!!! If you take it out of the circuit, the MOSFET is still "biased" on. It's sole purpose is to turn the MOSFET off. You could run the MOSFET directly from the 555... the problem is that the 555 doesn't have the current...
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    Milliamp Question

    You said you had a supply rated at: You said your load is only 200mA. Your supply is more than adequate for your load.
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    MOSFETS in parallel

    YES!!! Put the gate resistor in the collector of the NPN not to "over-drive" the MOSFET and the PNP will be able to turn it off faster. Most of our designs have PWM's capable of 1 or 2 amp's and if they don't, a driver is used.
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    MOSFETS in parallel

    With the values shown, it could switch at up to ~48KHz... your not going to drive that MOSFET with a 555 directly at that frequency.  A 555 can only sink ~200mA whereas the 2N2222 is good for 1A. Yes, exactly what I said in my original reply.
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    MOSFETS in parallel

    The 2N2222 can sink a lot more current than the 555, so the "turn off" will be faster... and thats a good thing. I'd even put a diode across the 10 ohm gate resistor to speed it up even more.
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    MOSFETS in parallel

    The 2N2222 is there to turn the MOSFET off. The 2N3055 gain is low. The 330 ohm will "slow down" the MOSFET turn-on. Why 4 MOSFETS in parallel? The IRF510 is a 100V 5.6A device with an Rds on of .54 ohms. You will need a snubber across the primary winding or MOSFET (maybe both). You show a 3A...
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    0-30 Vdc Stabilized Power Supply

    Or soldering a copper braid (i.e. Solder Wick) on top of the trace.
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    Front Panel Manufacturing for Electronic Equipments

    You could check out: http://www.frontpanelexpress.com/
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    [b]Questions regarding Switched-Mode Power Supply[/b]

    Well, you could have an "off-line" or a DC-DC converter... both are considered SMPS. In an off-line switcher, the AC is rectified & filtered (then a PFC stage in most) and then fed to a DC-DC converter. The "switch mode" part is that the DC voltage is "chopped up" (switched on and off)...
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    Re: Ldi/dt of an inductor

    And why do you think an inductor is gong to behave differently just becasue you apply a different type of signal (waveform)??? The answer is... it won't... all "the rules" (or math, if you will) that govern their functionality apply all the time! Why do you think: Do you know why the diode...
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    Charging/Switching efficiency

    What is going to be "charged" at 410VDC??? Those spec's seem to be for the front end of a off-line SMPS.
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    0-30 Vdc Stabilized Power Supply

    The problem is that there is only one point in the feedback path that contains all the feedback information from both loops, and that would be between the R12, C6 & C9 node and the R11 and U2 pin 4 node... but I'm not sure it's a legitimate injection point. The same rules should apply here...
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