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  1. AnalogKid

    Simple Waveform Generator Help

    A more common approach from the 70's is to use an 8-bit shift register instead of the Johnson counter. ak
  2. AnalogKid

    Simple offset voltage question

    There are several online simulation sites that do not require any software to be downloaded and installed, but I've found them to have relatively low performance and limited capabilities; to the point that I no longer track them to see if they have improved. Linear Technology Spice (LTS) is the...
  3. AnalogKid

    What is the component

    know where this symbol came from. Please post a larger section of the schematic. Absent that, I vote with HK - a pcb-mount ferrite bead with an impedance of 120 ohms at some specified frequency (typically 100 MHz). ak
  4. AnalogKid

    Simple Waveform Generator Help

    First, the bad news. He shows the circuit running on a single 9 V battery. It will not. It needs both plus and minus supplies. This can be two 9 V batteries in series, with the common point as the circuit ground. Note that there is no ground symbol anywhere in the schematic. This tells us...
  5. AnalogKid

    Generating two complementary signals on 12 V supply on/off

    Ummm ... no.
  6. AnalogKid

    Generating two complementary signals on 12 V supply on/off

    Something like this. Signal flow is left-to-right and monotonic, as opposed to the 12 V ON signal reversing direction twice. Also, R1 is shown more clearly as the series leg of a 2-resistor attenuator. Note that this is clipped out of a standard A-size schematic page with a zone id border...
  7. AnalogKid

    Generating two complementary signals on 12 V supply on/off

    53, but . . . It wasn't complaining, just pointing out that a discussion of electronic circuit analysis without reference designators is beyond cumbersome. The other post also was not complaining. Unlike some other forums, this one encourages discussion and instruction. That was instruction...
  8. AnalogKid

    Generating two complementary signals on 12 V supply on/off

    Strongly disagree. Besides the typing efficiency (2 keystrokes versus 25 (!)), that idea does not work for any schematic with multiple similar circuit stages and/or non single-transistor subcircuits. It also does not work for anyone who does not know as much as the original designer, such as...
  9. AnalogKid

    Generating two complementary signals on 12 V supply on/off

    Maybe. That's why I asked question #3. If the output of the 12 V supply wanders down to 0 V slowly (very possible with a light load), the slew rate might be below the 10 uF (reference designators) - 2 K (reference designators) differentiator time constant. The transistor (not that one, the...
  10. AnalogKid

    Generating two complementary signals on 12 V supply on/off

    1. Is this the actual 12 V output, or some kind of status signal? 2. How much current can it source and sink? 3. How fast is it? Specifically, are both its rise and fall times less than 1 ms? 4. The resulting pulses might not go all the way down to 0.0 V. What is the maximum low signal...
  11. AnalogKid

    Generating two complementary signals on 12 V supply on/off

    Did it occur to you for even one millisecond that we might need actual information about the pulses? ak
  12. AnalogKid

    Looking for help finding/searching for a "inline DC power plug & jack"

    Free-hanging, 1 to 5 A rated, in stock: Females...
  13. AnalogKid

    Generating two complementary signals on 12 V supply on/off

    When the 12 V goes on or off, do you want a pulse at the corresponding input, or a continuous low level as long as the 12 V is in that state? For continuous (steady-state) signalling, then dividing the 12 V down to 5 V with two resistors will create a signal that is high when the 12 V is on...
  14. AnalogKid

    What's bridge purpose in connecting the two functional circuit

    It is not feedback. C8 is a coupling capacitor. Both sides of the bridge are driven from the Q3 collector. ak
  15. AnalogKid

    Can someone help identify this device?

    Agree. The flywheel is so large compared to the magnet/coil pole surface area that I think very little useful power will be produced when running as a motor. OTOH, as a generator that large diameter works to your advantage; a low power motive source such as a toy steam engine will be able to...
  16. AnalogKid

    Can someone help identify this device?

    Looks like a lab demonstrator of a DC motor. Way older than 50, maybe pre-WWII. ak
  17. AnalogKid

    Generating two complementary signals on 12 V supply on/off

    Any voltage monitor, from a relay to a microcomputer, has a detection range for good and a detection range for bad. Usually this is simply a voltage level. For example, if the 12 V source might vary by +/-10%, then a comparator with a trip point of 10.8 V will give you a basic present/not...
  18. AnalogKid

    transformer use question

    All you have is all there is. In AC power calculations, VA is just that - volts times amps. 24 V times 0.5 amps (post #3) is 12 VA. This is the apparent power. AC power is way more complex (!) that DC power. Phase angles, power factor, real and imaginary vectors . . . I'm not trying to...
  19. AnalogKid

    transformer use question

    Your valves are 12 VA peak and 4.8 VA continuous. AND they are designed for an AC input only. The current draw with a DC source will be different, and probably higher. ak
  20. AnalogKid

    transformer use question

    VA means volts times amps. The transformer is rated for 50 VA, so at 24 V that is a current capability of just over 2 A. At 0.5 A per valve, that is 4 valves. You can turn on up to 4 valves simultaneously. ak
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