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  1. K

    0-30V Stabilized Power Supply

    What about the opamp differential voltage? U2 has almost none. Because the gain is low. The resistance is low.
  2. K

    1-18volt variable power supply

    Modified. The 1-25volt variable power supply is the preliminary design.
  3. K

    0-30 Vdc Stabilized Power Supply

    I have this other 1-25volt variable power supply that may compare to this design. This one is great by design because the change in output voltage is inverted at the opamp input. The 1-25volt supply has higher gain.
  4. K

    1-25volt variable power supply

    This is a preliminary design of a variable power supply I might develop. All ideas and comments are welcome.
  5. K

    0-30V Stabilized Power Supply

    I'm wrong. The voltage regulation looks very good at around a gain of 3. RV1 doesn't need any offset adjustment unless the regulated output voltage is more than 15 volts.
  6. K

    0-30V Stabilized Power Supply

    The opamp having a very high voltage gain should regulate it's output at the voltage set by the offset RV1. The 0.85 gain of the negative feedback loop transistors combined with R12 is where the loss in load regulation is. However, the voltage response is quick.
  7. K

    0-30V Stabilized Power Supply

    The error amplifier opamp is two transistors away from the output. Low gain and high input current means low beta. So this isn't the best voltage regulator.
  8. K

    11.1 volts to 8.0 volts ?

    Doesn't he need a good voltage regulator to charge the battery?
  9. K

    How this ps unit works??

    Here's a better circuit.
  10. K

    How this ps unit works??

    Try this circuit. It is good for analogue only.
  11. K

    How this ps unit works??

    Hello Walid, the circuit you found was I think novice. Q3 is an NPN. Indulis recommends removing the resistors and I agree. The load has to be high impedance. Most versatile regulators need to sink current sometimes.
  12. K

    How this ps unit works??

    A center tapped transformer is perfect for producing a negative dc supply voltage. This one doesn't have one.
  13. K

    Inverter oscillator

    At 1cycle/3s the slew rate is probably too low to double the voltage. The 5kHz variation stopped working, probably it's a bad inverter. Don't have another one.
  14. K

    Inverter oscillator

    The original circuit. The voltmeter shows a positive voltage on the positive cycle always 300mV.
  15. K

    Inverter oscillator

    It's the charge and discharge on the capacitor. A discharged capacitor doesn't have to discharge, a charged capacitor has to discharge.
  16. K

    Inverter oscillator

    It's a CMOS inverter oscillator. The voltage will double, then the inverter will fail.
  17. K

    Inverter oscillator

    I finished the circuit. It is uses two inverters, capacitors, and resistors. The resistors pull up and the output is about a cycle every few seconds. There isn't a gate resistor connected to ground.
  18. K

    Inverter oscillator

    The difference between the TTL and CMOS inverter oscillator if I recall is the CMOS inverter following the feedback capacitor needed a gate discharge resistor. The TTL circuit used a pullup instead of pull down resistor for this difference. Was I missing the gate discharge resistor?
  19. K

    Inverter oscillator

    I'm designing a simple inverter oscillator. There are one or two designs depending on if the logic is bipolar transistor or fet. Is it the bipolar transistor logic which requires a 0v sink current? Does the fet logic only require nothing to output high?
  20. K

    field effect transistors

    Can field effect transistors be used at a very low current in a common drain amplifier?The source resistance is very low and a high reverse VGS is used.
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