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  1. K

    0-30 Vdc Stabilized Power Supply

    Hello Again! Took me a little while to digest the latest post but I think now that I am set!  The equations made it all clear and helped tremedously! One of the most confusing aspects to my understand went away when I (finally) realized that the Q2/Q4 transistors were configured as a...
  2. K

    0-30 Vdc Stabilized Power Supply

    Indulis Sorry to drop out like that but the family and I nicked off for a short holiday to New Zealand. The entire statement makes perfect sense.  The basic workings of an op-amp reduce the difference between the inputs to zero thru the feedback network.  For an op-amp the output must be at a...
  3. K

    0-30 Vdc Stabilized Power Supply

    I was asking the gain in hopes of getting to understand what is confusing me a litte better.  To that extent it IS an academic exercise.  Unfortunately I've never worked with a simulator so I don't even know how difficult that would be. Yes.  I realized that mistake after I had posted.  I see...
  4. K

    0-30 Vdc Stabilized Power Supply

    Indulis: I've been pondering on this all weekend. For the feedback loop to include D9, U2, R15, Q2, and Q4 wouldn't it have to include the load as well??  I don't see any path back to U3(-) input that doesn't include the load? Any guess as to what the gain would be? I'm currently looking...
  5. K

    0-30 Vdc Stabilized Power Supply

    Current regulator is a better term than current limiter.  I stand corrected! U3's output must go down to bring the difference between the inputs to 0.  What I cannot see is what is limiting U3's output to a mid level voltage.  It seems to me that any difference greater than 70uV should drive...
  6. K

    0-30 Vdc Stabilized Power Supply

    Audioguru: Sorry to continue on about this but I'm really trying hard to understand. It sounds like what you are saying is that the circuit is actually looking to use the open loop gain of the opamp of about 200,000 (110 dB) as per the spec sheet? The implication is that the total offset...
  7. K

    0-30 Vdc Stabilized Power Supply

    Good to be here.  I see some very interesting projects! How is it that U3 acts as a linear amplifier with no feedback? Or am I simply missing the feedback loop? Without feedback a difference of a few mV should force the output rail to rail (or as close as the op-amp can come).  Hence my...
  8. K

    0-30 Vdc Stabilized Power Supply

    Hi All: I've been studying this schematic and reading the two primary threads about this power supply for a few days now (and may I say special kudos to Audioguru and Kain for their fortitude in producing the 5A version). The circuit makes sense except for the current limiting function.  I'm...
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