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Type: Posts; User: BradtheRad

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  1. Closed: Re: [PIC] Car Cooling System PSU Design Related

    I think it's okay if you apply 4A at 50 percent duty cycle to each battery. (Don't know about 8A at 25% duty. Or 16A at 12.5% duty.)

    It's efficient if you maintain the power source at just a volt...
  2. Closed: Re: [PIC] Car Cooling System PSU Design Related

    It's okay to use mosfets with pwm although their low On-resistance may pass several (perhaps too much) Amperes to the batteries. More so when batteries are at low voltage. Therefore it's a good idea...
  3. Closed: Re: Cadence Orcad Pspice error (no more threads can be created in the system)

    Can you set a value for charge voltage on the output capacitor (and other capacitors)? After power-up, I find that it usually requires many operating cycles until capacitors charge so that a circuit...
  4. Closed: Re: [PIC] Car Cooling System PSU Design Related

    Simple method to charge two batteries in series, from one power supply. Drive a half-bridge so it alternately provides current to each battery.

    156802

    The diodes are necessary.

    One battery...
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    Closed: Re: Capacitor as a MOSFET in RC Circuit

    Simulation showing action of RC in series with source. Various amounts of phase shift are portrayed.

    Green waveform is voltage. Yellow is current. Current is always in phase with output voltage as...
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    Closed: Re: Capacitor as a MOSFET in RC Circuit

    The mosfet has an insulated gate with very high resistance. Try calculating the R*C time constant and it tells you what fast frequency you need to apply, in order to reveal capacitor action.

    In...
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    Closed: Re: Capacitor as a MOSFET in RC Circuit

    There is such a thing as a capacitance multiplier. Is that what you made?

    Test your RC network by applying a wide variety of frequencies.
    Somewhere in the middle is a frequency range which brings...
  8. Closed: Re: Charging Voltage for a 1.2V NiMH Battery

    If you make the battery rise to 2V, then expect it to send such great current through your battery that it heats up alarmingly. It's likely to shorten its useful life.
  9. Closed: Re: How to create a voltage selector circuit

    Try to devise XOR gates (exclusive-OR). A stack of them creates a one-dot graph effect as you need.

    I suppose you realize you could start with a window comparator made from several op amps. This...
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    Closed: Re: LM5642 buck converter not work

    Your schematic appears to be twin interleaved, buck type, synchronous operated.

    Try starting out with a single basic buck converter. Use just one mosfet and one diode (asynchronous operation). See...
  11. Closed: Re: Arduino based irrigation controller misbheaving at a particular site.

    * Try attaching a pulp or pull-down resistor where you see noise at a terminal. 1 Mohm is a reasonable value to start. Don't make it low enough to affect operation.

    * Check where sensor wires are...
  12. Closed: Re: Charging Voltage for a 1.2V NiMH Battery

    During charging a battery shows a rise in voltage. Even a healthy nicad or NIMH might go to 1.6 or 1.7 V. (When taken off charge it drops to 1.45 or so, settling down to 1.35 or 1.4 after a few...
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    Closed: Re: LM5642 buck converter not work

    Sometimes a load is needed in order to get any sort of normal operation. Try a resistive load whose value draws 5 or 10 percent of your intended current.
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    Closed: Re: Processor overheating

    Maybe water cooling is possible? Can you pump water on the enclosure? Or even hang a bag overhead and drip water onto it. A bagful of ice works for a time.
    Lay thin plastic film on the unit so salt...
  15. Closed: Re: Solving for derivative wrt 'variable name', for mode 1 out of 1 for H-field

    Is this the name of your variable?
    A variable name is supposed to consist of one word, not two words separated by a space.

    Or you can make it one word by removing the space.
  16. Closed: Re: Automotive toggle switch on PCB solutions?

    Of course it seems economical and efficient to attach the switch directly to the board, however...

    Do you intend for the switch to be exposed? Suppose a user were to press the switch with all his...
  17. Closed: Re: Seeking for zerocrossing switching without using microcontroller

    Therefore it's a reactive load. It may cause AC voltage crossings to be out of alignment with AC current crossings. Then you're not certain which you are sensing.
    Or it may cause continued current...
  18. Closed: Re: Converting AF oscillator to use discrete components

    Wien-bridge oscillator made from 2 transistors. A schematic is at website:

    http://www.circuitstoday.com/wien-bridge-oscillator

    156695

    Component values aren't labelled so I tried playing with...
  19. Closed: Re: Lead Acid + Super-Capacitor + DC/DC Converter

    To produce your desired power and step-up ratio, you'll probably need to make the boost converter draw some supply current at all times. Input filtering may provide only slight benefit.

    Here is a...
  20. Closed: Re: Steady State average Voltage Simulation in LTSpice

    Mostly you're interested in Ampere levels through various components.
    To measure DC current in a wire, install a low ohm resistor (sense resistor). Across it attach a series RC network. This smooths...
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    Closed: Re: Processor overheating

    Possible options:

    * Attach a large heatsink which has many fins. To fasten it to the enclosure you may need a high-tech adhesive which is thermally conductive. Or use clamps, etc.

    * Peltier...
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    Closed: Re: Implementation of sine cosine using LUT

    For angle less than 42 degrees from horizontal, multiply by ∏/180 to get sine within 10 percent error.
    Thus 30 degrees x ∏/180 = .5236. Correct value is .5.
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    Closed: Re: Need circuit of Charger sans-fill

    You can get 5V output, by means of a voltage multiplier, or boost converter.
    One is based on capacitors, the other on an inductor.
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    Closed: Re: Implementation of sine cosine using LUT

    We can generate a look-up table of sines from 0 to 45 degrees by starting with .7071 (sine of 45 deg), and taking equal proportions.

    Thus for 1 degree we take one 45th of .7071. This gives us...
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    [SOLVED]Closed: Re: EPSON M-T532 on Arduino Uno

    I persuaded my VIC-20 computer to send to my Macintosh over 2 wires (a null modem arrangement). I did not need to use the handshaking lines. Likewise it may be possible for your setup. You might need...
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