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  1. Hero999

    Simple voltage regulator

    It appears as though you've confused the non-inverting and inverting amplifier topologies. As we said many times in the thread linked to above, you need to build a non-inverting amplifier with the negative feedback taken from the output side of the buffer. Read the documents linked below. If...
  2. Hero999

    what is the procedure for calculate the clearance between two trace

    I've told you before on the other forum: you haven't provided enough information; the clearance between two 3.3V traces is as small as the PCB manufacturer can make. http://www.eevblog.com/forum/beginners/what-is-the-formula-for-distance-between-two-trace/msg570584/#msg570584
  3. Hero999

    Simple voltage regulator

    We had this discussion 7 months ago. Have you forgotten? Here's a link to the thread so you can remind yourself: http://www.electronics-lab.com/forum/index.php?topic=38954.0
  4. Hero999

    Can someone identify what these diodes are for?

    Yes, it's an OR network. The diodes make it so the op-amps can only divert current away from the bases of the driver transistors. A1 is the voltage error amplifier and A2 is the current error amplifier and the OR network stops them from fighting one another. The drop-out voltage will be huge...
  5. Hero999

    stepper motor output waveform

    Yes, you need an oscilloscope. Spin the motor at a constant speed, perhaps use a drill but don't go too fast as very high voltages will be produced, and measure the waveform using an oscilloscope.
  6. Hero999

    New Power Supply II

    The op-amp will need a negative supply to compensate for the diode voltage drop and that of the op-amp's output stage.
  7. Hero999

    Frank Huges transistor tester

    According to the text. The circuit was originally designed for TTL and has been modified to use CMOS. Try using 74HC ICs and a low drop out 5V regulator, such as the LM2936-5.0.
  8. Hero999

    New Power Supply II

    That won't regulate the voltage though, will it? What's the output of the current amplifier when the the non-inverting input > inverting input? You need to design it so the current amplifier can only reduce the output voltage, not increase it.
  9. Hero999

    stepper motor output waveform

    I've never tried this myself but I'd suspect it's neither square nor sine. It's probably a messy waveform. The number of steps will determine the number of cycles per revolution.
  10. Hero999

    New Power Supply II

    The only real solution to the stability problem is to use an emitter follower on the output.
  11. Hero999

    Dual 1-15V± tracking

    I've does this before but I used voltage regulator ICs which have built-in over current protection. A transformer needs to be de-rated when used to power a rectifier and filter capacitor so a 1A transformer may overheat if 1A is drawn from the DC side continuously.
  12. Hero999

    New Power Supply II

    As long as Q1 is a common emitter amplifier there's a risk it'll oscillate, especially under certain conditions (a large capacitor connected to the output with a low ESR). This is because you've introduced another pole with a phase shift influenced by the load impedance...
  13. Hero999

    Power Designs 2020B concept build idea

    Here's the schematic, inverted and converted to monochrome to make it more clear.
  14. Hero999

    advantages/disadvantages of auto-ranging DMMs

    Fortunately all decent autoranging DVMs allow the range to be set manually (the meter linked to above does), so range hunting it's a non-issue.
  15. Hero999

    Supercap charging

    The voltage across the capacitor should never exceed its rated value, indeed it's a good idea to leave a safety margin of at least 10%, so it it's rated to 2.7V, keep the voltage below 2.43V. Supercapacitors are polarised and should never be subjected to reverse voltage for any period of time...
  16. Hero999

    I have a problem form Amplifier voltage divide

    After correcting liquidbytes's simulation, the steady state power dissipation in R6 is 3.9994µW.
  17. Hero999

    I have a problem form Amplifier voltage divide

    You need to wait until the steady state, before attempting to calculate the power in the load. When the power is first applied, there will be a power surge as the DC bias voltage stabilises; it takes awhile for the capacitors in the circuit to charge. Once the steady state has been reached, the...
  18. Hero999

    replace my multimeter?

    Yes you probably need a new meter and make sure you buy a reputable brand and not something cheap, so it lasts longer.
  19. Hero999

    Power supply short circuit protection.

    I don't see how the circuit can work anyway. The problem isn't the power supply voltage. If the op-amp rated to be run off a bipolar 22V supply, then it should be fine on a 36V single rail supply.
  20. Hero999

    An interesting question about capacitor

    I don't understand the question. If both the plates of a capacitor are at the same potential, then there will be no charge on the capacitor.
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