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  1. crutschow

    Recharging 7.2V 700mAh battery circuit

    Are they really NiCd, not NiMH batteries? Properly charging NiMH/NiCd battery requires careful control of the charging current to achieve full charge with damaging the battery, as stated in this article. The circuit you posted is unlikely to do that.
  2. crutschow

    Latching switch

    I know what your definition is. ;) I wanted to know what the TS's definition was.
  3. crutschow

    Latching switch

    What is a "latching switch"?
  4. crutschow

    General question about 12 volt inverter hookup in vehicle

    I wouldn't use anything smaller than 4 gauge which is rated for 120A.
  5. crutschow

    General question about 12 volt inverter hookup in vehicle

    Looks like 1ga, so it's plenty large for that current. No, it's not a good idea to run that much current through the chassis. The connection would be through the battery ground connection to the motor and then the motor connection to the chassis, but I don't think that motor to chassis...
  6. crutschow

    General question about 12 volt inverter hookup in vehicle

    The is no difference in which connection has the higher resistance, since they in series and just add together to make the total resistance of the circuit. 750W will draw a minimum of 750/12 = 62.5A (likely closer to 75A actual). Having that amount of current flowing through the car chassis is...
  7. crutschow

    Please help me use a PWM alternator for a project

    Since that is an open-loop adjustment, I trust you realize that you will need to connect a voltmeter to adjust the battery charging voltage to the desired value.
  8. crutschow

    Please help me use a PWM alternator for a project

    From all I've read, that smart alternator requires a PWM signal from the PCM to control it's output voltage, so don't see how you can use that alternator for what you want to do, unless you can determine how to generate that required signal. :(
  9. crutschow

    Circuit not working like intended...help please!

    You should always breadboard a circuit before building a PCB, if possible, to make sure there are no errors and the circuit works as intended.
  10. crutschow

    Help wiring vintage record player speaker

    So do you plan on hooking up the speaker electromagnet to the radio circuit or use an external DC source? If you want to use an external DC source, you would just have to apply an increasing DC voltage with audio to the voice-coil until the audio output sounds normal. The normal DC current...
  11. crutschow

    Make something move up and down with a push of a button

    I used the schematic drawing program on the free LTspice circuit simulator downloaded from Analog Devices.
  12. crutschow

    Make something move up and down with a push of a button

    If you want to save some money, you could also use a salvaged windshield wiper motor, which can give a reciprocating output.
  13. crutschow

    Ignition Coil Fence Charger

    Let us know how it works.
  14. crutschow

    Ignition Coil Fence Charger

    About 10J. Below is the LTspice sim of the circuit which stores 10J in the capacitor: It is directly powered from the line (be carful when working on it and only plug it to a GFCI socket) so the required isolation to the fence is provided by a dual-output (lost spark) type coil which is isolated...
  15. crutschow

    Make something move up and down with a push of a button

    Yes, but it would require some additional electronics with a light sensor and some simple logic but since this is a school project, I can help you, but can't do the work for you (unless you want me to get your school marks :-) You need to develop the basic design to do what you want, and show...
  16. crutschow

    How to power 2 motors that rotate in different directions with 1 power source, without tangling cables.

    Then you don't understand how slip-rings work. Look them up.
  17. crutschow

    Make something move up and down with a push of a button

    Don't follow your concern (?) as the reversal is provided by the crank and connecting rod. It just keeps rotating in the same direction, making the connecting rod move up and down. The limit switches would be positioned so that the rod or crank pin activates one at the top of the stroke, and one...
  18. crutschow

    Ignition Coil Fence Charger

    Ran into a problem. My simulation shows high dissipation in the SCR trigger when I increase circuit values to handle a 20J pulse. I'll think some more about that, but have no obvious solution presently.
  19. crutschow

    Ignition Coil Fence Charger

    Say you pulse one 20J pulse per second, that's 20W average power. So a typical 50Ah, 12v car battery would last for (50A*12V) / 20 = 30 hours, not counting any inefficiencies. You would need a 100-200W solar panel to keep the battery charged, depending on your location. I have generated a...
  20. crutschow

    Ignition Coil Fence Charger

    If it doesn't say, then you need to determine the value of the charge capacitor, and the voltage it is charged to. No. Likely the only way if you want 20J of spark energy. What power do you have available to power the fencer circuit?
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