Search results

  1. CircutScoper

    2 latching relays, 2 pushbuttons, 2 dc 5 Volt motors and 4 limit switches

    Because both pairs of relay coils are connected in parallel, one pair of diodes serves both.
  2. CircutScoper

    The emitter has a higher potential than base ! How?

    At what time mark is that said? I'm not watching the whole stupid thing.
  3. CircutScoper

    A simple electric fence idea

    True that current (no pun) versions do, but early ones used AC. The principle is the same.
  4. CircutScoper

    A simple electric fence idea

    Defibrillators work by arresting the heart.
  5. CircutScoper

    A simple electric fence idea

    BTW, 10mA of arm-to-arm AC is, as I recall, near the maximum of the lethality-vs-current curve, because it's just right to induce self-sustaining ventricular fibrillation. Less is harmless, while more will induce total cardiac arrest, which sounds worse but isn't because it will spontaneously...
  6. CircutScoper

    A simple electric fence idea

    Yup. Gone are the days when "Enter at your own risk" could mean what it says. Now, of course, it only means "Enter at mine."
  7. CircutScoper

    A simple electric fence idea

    Good thoughts. Ultimately, and depending on the size of the critters you need to discourage, it may come down to a SWAG tradeoff between the likelihood of unexpected human-trespasser contact with your fence when it's live, and just how desperate you are to deter the varmints.
  8. CircutScoper

    A simple electric fence idea

    Well, if your microwave xfmr provides isolation between primary and secondary, why not revisit your original idea of a fence with direct AC excitation and simple impedance limiting to hold the current to a safe level? You might need to provide a grounding surface (e.g., a few square yards of...
  9. CircutScoper

    2 latching relays, 2 pushbuttons, 2 dc 5 Volt motors and 4 limit switches

    Oh, okay. Maybe you live in a land where latching relays are cheaper than diodes.
  10. CircutScoper

    2 latching relays, 2 pushbuttons, 2 dc 5 Volt motors and 4 limit switches

    If you want to unnecessarily waste a relay, go for it.
  11. CircutScoper

    2 latching relays, 2 pushbuttons, 2 dc 5 Volt motors and 4 limit switches

    You can do it with a standard relay.
  12. CircutScoper

    2 latching relays, 2 pushbuttons, 2 dc 5 Volt motors and 4 limit switches

    Que anon. When a limit switch is pushed open, the corresponding motor stops, holding the limit open and the motor stopped.
  13. CircutScoper

    A simple electric fence idea

    200ms then? Practically all day!
  14. CircutScoper

    2 latching relays, 2 pushbuttons, 2 dc 5 Volt motors and 4 limit switches

    Why not just one relay?
  15. CircutScoper

    A simple electric fence idea

    "Quickly unplug" is right! With only ~1/10th second between 80V and 90V, seems a pretty good reaction time would be needed to use this method!
  16. CircutScoper

    A simple electric fence idea

    Good idea! And be sure to leave the multimeter connected while you're waiting. That way, loaded by the meter input resistance, C2 should take "only" a couple of hours to bleed down (I.e, RC ~ 10M x 470uF = 4700 seconds). Otherwise, it could take weeks.
  17. CircutScoper

    A simple electric fence idea

    A practice I adopted in days of yore was to do every first smoke test of any line-powered gadget with AC supplied from a Variac (or similar) autotransformer slooooowly dialed up from zero while checking supply voltages and copiously and continuously sniffing. Saved a lot of rework. And smoke...
  18. CircutScoper

    2 latching relays, 2 pushbuttons, 2 dc 5 Volt motors and 4 limit switches

    Hi, Harry. Question: Your schematic suggests that your "actuator" limit switches are normally closed, and open (breaking the circuit) when your motors arrive at the limit of their motion cycle. Is this true, or are they normally open and close at motion limit? If the former is true, then I...
  19. CircutScoper

    A simple electric fence idea

    Long decades ago, a CalTech pal and I got into an (only moderately drunken) argument about how train crossing signals detected the presence of an oncoming train. He maintained it involved sensing weight while I voted for a simpler method based on electrical conductivity between the rails. So...
  20. CircutScoper

    A simple electric fence idea

    Speaking of "shorting out," I wonder how many manly "Boy Electrician" readers contrived to conceal a length of stout copper wire spanning the distance from the palm of one hand, through the sleeves and back of their jacket, to the palm of the other? Imagine how impressed the crowd would have...
Top