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  1. crutschow

    Lead acid battery minimum discharge level

    Discharging them to 10.5V (or below) won't. Discharging standard lead-acid batteries to a low level can damage the plates due to shedding of lead sulfate from the plates. Thus, for best life, it it recommended that standard Pb-acid batteries be discharged to no more than 50% of it's capacity...
  2. crutschow

    how to create autoswitching circuit for 12v ups for router

    As I said, it depends upon the relative voltage between the power supply and the battery. Which voltage is larger and by how much?
  3. crutschow

    how to create autoswitching circuit for 12v ups for router

    If the 12V adapter voltage is slightly higher than the battery voltage, you could use a Schottky diode at each output to isolate the load. If the adapter can tolerate the battery voltage on its output when it is unpowered, than you only need one diode. If adapter voltage is not larger than the...
  4. crutschow

    Pulsate 1.5v D cell battery

    Below is the LTspice simulation of a two BJT astable (relaxation) oscillator the operates from 1.5V, and uses a capacitor doubler circuit to generate a short periodic current pulse (red trace) in an LED (since 1.5V is not enough to power a visible LED):
  5. crutschow

    Pulsate 1.5v D cell battery

    For 1.5V operation you might be able to use a BJT astable oscillator. But what load are you trying to drive with the 1.5V signal?
  6. crutschow

    How do I measure a material's capacity for ultrasonic media use?

    Define what you mean by "ultrasonic media use"(?).
  7. crutschow

    Can Damper Diodes be used at high duty cycle current?

    They can be used at a higher duty-cycle as long as the maximum average forward current rating is not exceeded.
  8. crutschow

    What is quality level and reliability of cheap chinese diodes?

    No matter what, you need low current ( a couple hundred mA), fast recovery diodes, (such as Schottky types) to rectify 20kHz signals. Larger diodes have more junction capacitance which can affect the accuracy of the rectified signal.
  9. crutschow

    Inrush Current for Capacitive Load

    A step input has infinitely high Fourier frequency components, so the initial capacitive impedance is zero, not infinite.
  10. crutschow

    Issues with kenwood KAC-511 1000w amp

    How many subs are connected and what is their impedance?
  11. crutschow

    Help with what to check next - pre-amp distorting at high/full volume

    Likely it's a design problem with the amps not having enough dynamic range, so they clip the signal at high levels. Don't see how you can solve that without having a circuit schematic. Does it have an internal power supply?
  12. crutschow

    How do I make an opamp stereo mixer?

    What do you mean? What is "that"?
  13. crutschow

    How do I make an opamp stereo mixer?

    Okay, like this:
  14. crutschow

    How do I make an opamp stereo mixer?

    Okay, I think I better understand what you mean. So if the resistor value to ground is reduced further relative to the pot resistance, than the mid setting attenuation will be higher. For example, below is the plot for a 3kΩ added resistor: That gives a midpoint output of -25.4dB relative to the...
  15. crutschow

    How do I make an opamp stereo mixer?

    You just need an audio op amp that can operate at 5V. Look at the OPA134, OPA2134 and OPA4134, or the MC33171 single, MC33172 dual and MC33174 quad opamps, or the MC34071, MC34072 dual and the MC34074 quad.
  16. crutschow

    How do I make an opamp stereo mixer?

    What do you think midscale should be for a log response? Actually it's a reasonably good curve (simulation below of pot output versus wiper position): The yellow curve on the bottom would be straight if it were perfectly logarithmic, since the left axis is plotted on a logarithmic scale. As you...
  17. crutschow

    How do I make an opamp stereo mixer?

    Below is the portion of you need from the circuit Bertus referenced if you just want the mixer and don't need controls: For a gain of 1, change R115 to the same as the input resistors, 10kΩ. You an operate that circuit from a single 5V supply (connecting U3A's pin 4 to ground) if you generate...
  18. crutschow

    Differential coax cable vs 2 single ended coax cables

    If there is external radiated noise, it could affect the differential signal differently if the two cables are not close together. The difference likely would be small, but keeping the cables close together will minimize it.
  19. crutschow

    Differential coax cable vs 2 single ended coax cables

    For a flat band at that frequency you would likely want high speed shielded, twisted-pair and connectors such as these. If obtaining those types are a problem, you could try the two coaxes and see how it works, if you have that option. If so, make sure the two coax cable are as identical as...
  20. crutschow

    Differential coax cable vs 2 single ended coax cables

    The cable will introduce little noise. What is the nature of the signal and its level? It's just more complex, and any differences in the two cables will introduce differential distortion and noise into the signal. If you have a differential signal, then you should use a single differential...
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