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  1. Closed: Re: convert voltage control to current control

    There is - or should be - no contradiction - you can use a very small amount of current mode control in an half bridge ( but not too much ..! - the rest of the ramp comes from Vin - suitably...
  2. Closed: Re: Testing Amps on rewound microwave transformer

    The current needs to be limited by a suitable load on the output of the Tx - if you apply a too low ohm load you will overload the Tx, this is what fuses and polyfuses & circuit breakers are for ...
  3. Closed: Re: Testing Amps on rewound microwave transformer

    also the pri of a uWave Tx has fewer turns than a conventional Tx - it runs very high peak flux and high peak magnetising current - as a result they hum loudly

    you cannot connect an ammeter...
  4. Closed: Re: Earth leakage Detection "positive" as well as "Negative" >30mA.

    here you go :-157368
  5. Closed: Re: LoopGain analysis with multiple feedback loop

    @ The Electrician - they are resistors -
  6. Closed: Re: Need to reduce drain voltage spike in LM5019 Buck converter

    if you short your "probe" on the Vin line and still see the spikes - you know it is the probing system - you can subtract the artifact spikes from the signal.

    you can also short your probe on...
  7. Closed: Re: Need to reduce drain voltage spike in LM5019 Buck converter

    could be partially your scope - see how you have a spike on the current - where no spike should be - e.g. at turn off the current simply cannot jump high - so there is some artifact on your...
  8. [SOLVED]Closed: Re: Need very basic R-C "delay off" circuit

    yes - for a fast turn on the diode points to the base of the Darlington, i.e. cathode to base ...
  9. Closed: Re: Earth leakage Detection "positive" as well as "Negative" >30mA.

    you set up a balanced 30mA using a class B amp structure with the earth in the middle - that way if either the + or - is pulled to earth by more than 30mA a resistor volt drop can be used to...
  10. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    So you want full cycles of control ( 20mS for 50Hz ) or multiples thereof, zero crossing detect opto coupler and a ckt that keep the firing on for 15mS - the SCR / triac will then turn off at...
  11. [SOLVED]Closed: Re: Need very basic R-C "delay off" circuit

    across the timing resistor 220k, if you apply 3v3 or 5V to the 220k it will take a while for the volts to come up to 1.1V necessary to turn on the darlington array of xtors ( 2 x npn ) the...
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    [SOLVED]Closed: Re: 12V power source without any IC.

    here you go, this link contains schematics that will supply what you want ...
    ...
  13. [SOLVED]Closed: Re: Need very basic R-C "delay off" circuit

    if you use darlington connected xtors (bjt's) to turn on the relay, emitter gnded, then you can have 4u7 on the base to gnd and 220k drive resistor to the base which will give you a delay, ...
  14. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    Most 1st world countries require that the net average DC over a 24 hour period be 5mA or less - this to prevent earth stake corrosion

    If you draw too much pos cycle only power ( or neg ) you...
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    Closed: Re: DC Booster for Solar Pump

    agreed - you need a peak power ckt to draw the max from the panels ( even on on a sunny day ) and batteries to store (hopefully) the excess so that the load can run at other times, i.e. early...
  16. Closed: Re: Resistor at input to high side current monitor IC

    "Transient Protection
    Add a protection resistor (RP) in series with the LOAD
    pin if VSENSE can exceed 5.0V in positive sense or 600mV
    in negative sense, whether in steady state or in transient...
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    Closed: Re: 1.5kw DC to DC Boost Converter Circuit

    if you measure the high side gate drive w.r.t. 0v then you will see the totem pole shift + the gate drive signal ...

    - - - Updated - - -

    you need a differential probe - or isolated scope ...
  18. [SOLVED]Closed: Re: Technique behind the Charging and Inverting Function of an Inverter

    you cannot use the same Tx to charge the battery without some sort of boost circuit to raise the output of the rectified low voltage winding ...
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    Closed: Re: DC Booster for Solar Pump

    look up "boost converters" used a lot in transformerless grid tied inverters to step up the PV panels to 380VDc for inversion to 230Vac ...
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    [SOLVED]Closed: Re: Transformer saturation & ACM control

    Seems unlikely you will get 3kW continuous through an ETD54 at 50kHz - what is your calc Bpk under these conditions? Usual way to stop flux walking is a suitably sized DC blocking cap in series...
  21. Closed: Re: 16A 250V switch rated for 10000 ops at mains peak or zero cross?

    all AC switches arc - obviously more for higher currents and higher L in series - if the contacts open quick enough ( quality AC switch ) then as soon as the current drops to zero, ( it does...
  22. Closed: Re: Is this the reason there's so few 2 Transistor Fwd Sync Rect controllers?

    New chips generally require a lot of development time - as the companies supplying them simply do not test them in the way a real application does ...
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    Closed: Re: LT1248 PFC Controller

    you are forgetting the internal 7v5 reference again ...
  24. Closed: Re: Is it stable that phase drop to close to 0 but rise to 75 degree when gain is 0dB

    On the face of it - it is quite stable - adding other delays to bring the total delay to 360 deg is where it will start to oscillate - then the feedback reinforces the input - at 180deg...
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    Closed: Re: LT1248 PFC Controller

    "5" won't work, a bjt with emitter resistor for degeneration would be a better approach - remember 7v5 = 400V say

    so 2 V ripple on o/p = only 37.5mV ripple on the SS pin - a cap...
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