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  1. audioguru2

    0-30V Stabilized Power Supply

    The 7W power resistor is made to dissipate heat. it is made of substances that are fine when very hot. 2.24W is not near the 7W max rating so it is fine.  A power resistor operating at its max power rating will be extremely hot and will char the pcb, burn you if you touch it and melt plastic...
  2. audioguru2

    0-30V Stabilized Power Supply

    Each resistor is dissipating only 2A squared x 0.56 ohms= 2.24W. Yes because an electrolytic capacitor has "dielectric absorption". RV2 is adjusted for an ouput voltage of 0.0V when the voltage pot P1 is set to zero. RV2 is supposed to adjust only about plus or minus 0.05V to cancel the...
  3. audioguru2

    5000 watt stereo amp

    5000W is ridiculous for a home-made amplifier. It has no output protection. It is very dangerous because its speakers are connected directly to the AC line voltage instead of using a normal isolated power supply. It uses twenty expensive output transistors that might not be available anymore...
  4. audioguru2

    High Voltage low amperage

    An extremely heavy car battery? Didn't you hear me that it uses 200W? A transformer is driven from an oscillator (a 200W power oscillator for yours). A TV flyback is tuned and operated at the TV's horizontal frequency (15,750Hz in North America). The output of the flyback transformer is AC.
  5. audioguru2

    High Voltage low amperage

    10,000V at 0.02A is 200W which is a lot of power for a little power supply.
  6. audioguru2

    0-30 Vdc Stabilized Power Supply

    You had the NPN transistor Q1 where the PNP transistor Q3 should be? Then you had the PNP transistor Q3 where the NPN transistor Q3 should be? No wonder it didn't work. Your TL081 opamps are operating with a total supply voltage that is too high for them so they might fail soon. Your tiny old...
  7. audioguru2

    0-30 Vdc Stabilized Power Supply

    U3 compares the voltage across R7 with the voltage at current adjust pot P2. Since there is no load then there is no voltage across R7 so the inverting input of U3 is 0.0V. The non-inverting input of U3 has 10.6V across R18 plus P2 so it has a voltage of +5mV. The TL081 opamp has a max input...
  8. audioguru2

    Class D Bass amplifier

    The Philips TDA8920 class-D dual amplifier IC is a good one.
  9. audioguru2

    Electronics Eavesdropping Device Detector

    Hi Globby, People who built the project found that it doesn't work. Its first opamp has a lot of gain but does not have an input offset voltage nulling trimpot so frequently with no input signal the voltage controlled oscillator oscillates all the time, or if the offset is negative then the...
  10. audioguru2

    How do I calculate the voltage drop of a full wave bridge rectifier?

    When you rectify an AC voltage with a rectifier then you probably want DC. But the output of a rectifier without a filter capacitor is pulsing DC but an ordinary DC voltmeter reads the average voltage. A pretty high value filter capacitor will produce a smooth DC voltage that is 1.414 times...
  11. audioguru2

    0-30V Stabilized Power Supply

    Whose parts list? I think Redwire added a fine voltage adj. pot. The original version and my versions never had a fine voltage adj. pot.
  12. audioguru2

    0-30V Stabilized Power Supply

    I have never seen fine and coarse controls on a power supply. Usually they use a big knob so it can be fine and coarse.
  13. audioguru2

    0-30V Stabilized Power Supply

    Hi lu2dlt. Your English is not clear. What is "source query"? What is "offset lower intentions to 0 volts"? You did not say if you made the original project that has many problems including errors with its offset voltage adjustment. Or maybe you made the latest circuit that has no problems.
  14. audioguru2

    Linear response

    I do not understand what you are talking about.
  15. audioguru2

    Linear response

    Logic control is on and off. If it detects that the output voltage is too low then it can switch on full power until the voltage is high enough, then switch off. The output will be continuous waves of voltages. A linear error correction circuit has an opamp as its error correction amplifier...
  16. audioguru2

    0-30 Vdc Stabilized Power Supply

    China-man, Please do not post SPAM in this thread about the technical details for a lab power supply project.
  17. audioguru2

    0-30V Stabilized Power Supply

    The MC34071 is made by Motorola/ON Semi/Freescale Semi which is one of the largest semiconductor manufacturers in the world. The TLE2141 is made by Texas Instruments which is also one of the largest semiconductor manufacturers in the world. These opamps were chosen because their max allowed...
  18. audioguru2

    Is my Li-Ion bicycle light battery repairable?

    I have some Li-Ion cells sitting around for 10 years without being loaded nor charged and they still hold the original charge and work perfectly. You must never fully discharge a Lithium rechargeable battery! If it has a protection circuit inside then it will prevent a full discharge. Try...
  19. audioguru2

    OBSOLETE COMPONENTS

    Websites in India show many circuits that use obsolete components so maybe there are people there who hoard old parts then sell them.
  20. audioguru2

    Led display Digital Voltmeter question

    The datasheet for the ICL7106 for an LCD display and the ICL7107 for an LED display describes the problems caused by heating for the LED one. The heating causes an offset voltage that could cause the circuit to be out-of-range where most of the LEDs turn off which causes an opposite offset...
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