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  1. hevans1944

    Question for BNC terminator.

    The load simply makes the source-end of the cable appear to be driven by its characteristic impedance, 50Ω, but at the expense of attenuating the signal of the high impedance source. The key criterion you should look for is ringing at the pulse transitions. No ringing? No problem. Use whatever...
  2. hevans1944

    Cathode follower circuit for Rf generator

    As you noted, no tuned circuits in grid necessary to excite the 6146, although the usual pi matching network is needed to transform the plate impedance down to something a little more useful. My novice xmtr was a crystal-controlled oscillator of course, with some fancy circuitry for the keying...
  3. hevans1944

    Cathode follower circuit for Rf generator

    I am sorry I can't help with this one. It has been many years since I have "played" with cathode followers or the 6146 power tube (which I designed into my homebrew novice transmitter) using information available to me in 1966. This was mainly the ARRL Amateur Radio Handbook. If you can find one...
  4. hevans1944

    Question for BNC terminator.

    A lot depends on specific output characteristics of the device you are trying to observe with the oscilloscope. The DG535 delay generator appears to have several manufacturers. At least one of these has multiple output characteristics to match several popular loads, including high impedance, 50Ω...
  5. hevans1944

    Trying to find out the name of a type of component.

    Zener diode is correct.
  6. hevans1944

    Is this a good/stupid idea ? LED in //

    It is NOT a good idea. There is a resource here in this forum on how to drive LEDs. Do not connect the LEDs in parallel and attempt to drive them with a constant-voltage source!
  7. hevans1944

    boost converter

    The output voltage is determined by the resistive divider feedback network connected across the output, in conjunction with a 1.6 VDC internal reference on the LT3757 (for positive outputs). See the datasheet. Google is your friend here. The Linear Technology web site has extensive application...
  8. hevans1944

    First Soldering Circuit Board Attempt

    My DMM probes have a 6-32 male thread that allows the plastic barrel to be unscrewed to replace the test leads when they eventually wear out. I machined some copper slugs the same diameter as the inside diameter of the soldering ends of the alligator clips, drilled and tapped a 6-32 nut-thread...
  9. hevans1944

    The input voltage of the ADC chip

    What @Harald Kapp said. This device digitizes a single-ended analog input that nominally varies between GND and Vdd when PGA=1. Higher gain values will require a narrower input voltage range. See the datasheet. The ADC can also be used with differential inputs (the most likely application to...
  10. hevans1944

    Boost line voltage for LED Florescent bulbs

    Go to the web site @Windy Player cited and scroll down to see what's inside, and how to connect them in place of a fluorescent lamp. It specifically says you must remove the starter (if present) and short the two wires on an inductive ballast. All the magic, including LED constant-current...
  11. hevans1944

    Powered sub help

    Probably not if you need both + and - power with respect to ground. This looks like a switching buck-boost power supply and the output terminals probably share at least one terminal in common with the input terminals, one of which is your car chassis ground. So, depending on how it's designed...
  12. hevans1944

    Boost line voltage for LED Florescent bulbs

    You could purchase a low-voltage transformer, commonly called a control transformer, such as the one shown at the link. Wire it up as a "boost" transformer with the secondary in series with the "hot" side of the power line and the primary connected between "hot" and neutral. You need to "phase"...
  13. hevans1944

    Newbie Arduino questions

    I don't want to overwhelm you with details. As per usual, @KrisBlueNZ provided you with a nice overview of microprocessors in general. I think you should buy an Arduino Uno R3, a solderless breadboard, a couple dozen (or more) color-coded jumper wires to connect between the Arduino Uno and the...
  14. hevans1944

    Different answer using inverting op-amp and KCL?

    You can't just "forget about the inverting op-amp". The op-amp, acting as a voltage-controlled voltage source, connected between the op-amp output terminal and the ground node (your diagram does not explicitly indicate this) is providing current to the 96 kΩ load, as well as (it turns out) an...
  15. hevans1944

    Stumped - please help identify this connector

    Can you not simply replace both mating connectors with something else, rated for the current you expect to pass? As you noted, there are jillions of this style available.
  16. hevans1944

    Electronic Brake by wire system/regenerative braking

    The classic way to do this provides each wheel with a motor/generator, i.e., a motor that will also operate as a generator as well as a consumer of electricity, but not at the same time of course. The motor function provides motion to the wheels and builds up kinetic energy by virtue of the mass...
  17. hevans1944

    Tips for learning recursion?

    When first exposed to recursion in a computer science class, I thought it was pretty nifty. Later, I realized that the actual implementation (using stacks) made a real program non-deterministic! End of story for me. I think recursive code is right up there with self-modifying code as something...
  18. hevans1944

    Help calculating combined size of holes in a pipe

    A little algebra really simplifies things. Thanks @duke37 !
  19. hevans1944

    Help calculating combined size of holes in a pipe

    Okay, let’s start with diameters, stick with diameters, and finish with diameters. The area of a circle is A = (π) (D²) / 4. Where π = 3.14159 (approximately) You could use A = (π) r² but since D = 2r then r = D/2 and r² = D²/4 so we can work with diameter instead of radius. Most drills I have...
  20. hevans1944

    Help calculating combined size of holes in a pipe

    Following @KrisBlueNZ suggestion, I get an equivalent diameter of about 0.559 inches to equal the area of twenty 1/8" holes. What did you get?
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