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  1. hevans1944

    Wiper Motor Wiring

    If the power supply is well regulated, that should do the job nicely. By "well regulated" I mean the terminal voltage of the power supply does not change significantly from a nominal 12 V DC as the current demand increases from zero to its rated value of 5 A. You can check this with a load...
  2. hevans1944

    Wiper Motor Wiring

    I only see two wires disappearing into the motor. Is there continuity from either or both of these wires to the motor frame? If so, then the frame is the return lead and either the red or blue leads control the motor speed, per @Minder's comment. At 40 watts and 12 V, this motor will draw in...
  3. hevans1944

    Does anyone know the name of this connector

    Looks like. Grab an old PS2 mouse and look at its connector.
  4. hevans1944

    Does anyone know the name of this connector

    I don't see a picture.
  5. hevans1944

    Automotive coil on plug conversion HELP

    If I understand you correctly, you have three signals to play with: TDC, CYP, and IOS (Ignition Output Signal). The IOS currently fires the ignition coil four times for every two revolutions of the crank shaft. All you need to do is farkle with IOS to make four sequential firing signals: IOS1...
  6. hevans1944

    circuit of an IOT project

    Hmmm... lemme see... the crystal ball is cloudy today... where did I place that swami hat I purchased from the late Johnny Carson? Trying to channel schematics and block diagrams from the original poster (OP) but circuit is not showing up. Maybe someone can help me find my hat:
  7. hevans1944

    Help With Basic Seven Segment Display Counter Circuit

    The open-collector outputs serve to ground the cathode segments of the common-anode 7-segment display, thereby illuminating that particular segment. The resistor pack serves to limit the LED current when the 74LS47 output goes low. A pull-up resistor connected to the 74LS47 output does nothing...
  8. hevans1944

    Trying to make a transistor cancel another transistor

    There is a lot of criticism that could be made about the "schematic" that @David Lacroix made, photographed, and uploaded, but lack of contrast is certainly not one of them! Excellent job of drawing with high visibility of everything drawn in black ink on white paper. Good lighting for the...
  9. hevans1944

    Trying to make a transistor cancel another transistor

    Please post a schematic with part designations (R1, C2, etc.) and part specifications. Show electrolytic capacitor polarity if these are used. A well-lighted, high-contrast, hand-drawn schematic is acceptable. Use a dark felt-tip pen on plain white paper. Preview the image for clarity before...
  10. hevans1944

    sound frequency resulting from coil windings

    This is beginning to sound like an HHO scheme to get "free" energy from the electrolysis of water. Whether a stainless steel tube vibrating at some "magic" resonant frequency improves hydrogen production by a factor of ten is irrelevant. You simply cannot get more energy out than you put in by...
  11. hevans1944

    GPS NMEA, Failover Circuit upgrade attempt.

    just sayin'... if the two "rules" were always followed, dots would not be necessary. However, if the two rules are followed and dots are added at the "T" junctions, then there is no possible ambiguity, and the schematic is more readable. So, do all three: make connections at "T" junctions ONLY...
  12. hevans1944

    sound frequency resulting from coil windings

    Getting sound from electricity requires a transducer (Google that!) to convert electrical energy into sound energy. There are many ways to do this both intentionally (loudspeaker) and unintentionally (transformer hum). To excite your metallic object (such as bell) with sound waves is different...
  13. hevans1944

    Power From Sterling Engine

    If all you want is an "emergency radio" that operates from a heat source, a Stirling engine would not be my first choice. Delicate and expensive to build, inefficient, and too many moving parts to wear out or otherwise fail. During the Cold War, the Russians developed a multi-band radio that...
  14. hevans1944

    hi everyone

    Welcome to Electronics Point! Ask anything you like, but always remember to tell us what you are trying to DO first. You will get better answers that way.
  15. hevans1944

    sound frequency resulting from coil windings

    @jikwan: Welcome to Electronics Point! Hows about telling us what you are trying to DO before winding any coils?
  16. hevans1944

    Designing a Time Delayed Relay

    I liked the second method a lot better, but you do need to pay attention to the temperature of the soldering iron to avoid overheating the PCB and causing traces and (especially) pads to lift off. An SMD workstation with vacuum suction and a hot-air tip are on my shopping list... along with...
  17. hevans1944

    GPS NMEA, Failover Circuit upgrade attempt.

    This is a reply to a much earlier post on this thread, but I doubt it will be "one last thing"... :D There is a schematic drawing convention, probably invented because of the "disappearing dots" problem, that crossing lines NEVER represent connections. ALL connections MUST be "T" connections...
  18. hevans1944

    GPS NMEA, Failover Circuit upgrade attempt.

    They are trying to do something about it, both technically and diplomatically. It is a serious problem best discussed in a new thread rather than this one. Same applies to my proposed effort to build a DIY survey grade GPS with sub-centimeter accuracy thereby saving tens (if not hundreds) of...
  19. hevans1944

    Where can I buy a high voltage transformer

    One of our ion implant accelerators had a DC terminal potential of +250 kV with respect to earth ground on a good, dry, day. It still occasionally arced to ground for no apparent reason. The path through air was about two meters or so. It is almost impossible to create 400 kV in air without...
  20. hevans1944

    Where can I buy a high voltage transformer

    Firstly, transformers do not transform DC. Transformers transform AC. What power do you expect to get at 400 kV? What are you going to use this for? The only thing available to hobbyists that can produce 400 kV is a Tesla coil. You can't buy or build a 400 kV Tesla coil for two bux.
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