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  1. AnalogKid

    capacitor replacement in non-psu circuit.

    That advice sounds like either they think the capacitor will protect the device from overvoltage by failing into a short circuit when the condition occurs (it will NOT), or that they are talking about a zener diode rather than a capacitor. Either way, this is not the way to protect a circuit...
  2. AnalogKid

    12Volt to 5Volt converter

    Most car cell phone chargers have a simple non-isolated buck regulator, one of the standard switching power supply configurations. Usually it is a single chip with the voltage reference, switcher control circuits, and output transistor. This, plus a few external components and one inductor, is...
  3. AnalogKid

    Diode - Temperature

    Check with Linear Technology, Maxim, Analog Devices. Somebody out there has a chip that uses a diode as a temperature sensor and turns it into either a thermometer or a thermostat. ak
  4. AnalogKid

    SMPS Load Regulation

    For myself, for something sold in dozens of countries around the world, or for the military? ak
  5. AnalogKid

    SMPS Load Regulation

    No, it isn't. If it is beyond advanced persons, how did it come to Earth? Switchmode regulator chips are designed and manufactured by plain old Eathlings, circuits are taught in undergraduate and tech school classes, the mountain of design and applications information is available in many...
  6. AnalogKid

    SurgeProtector Strange behaviour

    Is the surge suppressor information secret also, or can we get the manufacturer/part number/schematic/whatever? ak
  7. AnalogKid

    SMPS Load Regulation

    It takes extra methods to get a linear power supply to regulate down to zero load, and it is even more difficult for switchers. The easiest way is to add a 40 ohm fixed load resistor to the output, raising the minimum output current seen by the circuit of 0.1 A. Try that and see if the...
  8. AnalogKid

    LED light driver

    Since there are no LED datasheets, all we have to go on is the information in post #1. Using the power rating and the median voltage for each LED type: first LED current = 1.15 A, 9x LED string power = 27 W. second LED current = 0.833 A, 3x LED string power = 9 W. It looks like the LED driver...
  9. AnalogKid

    How to make a capacitive power supply for 1W LED

    Thank you for sharing. ak
  10. AnalogKid

    voltage output slowly decreasing by .01 why?

    0.01 V out of 24.1 V is 0.0415%. That's not much. The LM317 is a great part, but it is not a millivolt or microvolt-precision device. If you combine the line and load regulation and tempco, I think you'll see that you are within the specs for the part. What is it about your application that...
  11. AnalogKid

    Multiplexer IC for analog inputs

    ADG1504 ADG5404 ak
  12. AnalogKid

    switch to detect movement of a wheel

    What power is available for the module? Is a relay acceptable for the switch? How about a power transistor? Size or weight restrictions? Weatherproof requirement? ak
  13. AnalogKid

    RF receiver circuit

    Yes, although all of the impedances do not have to be equal. For example, your filter could have a 50 ohm input impedance to match the source but a higher output impedance into the next stage, as long as that stage is designed for a higher source impedanc.. In general, however, most designs...
  14. AnalogKid

    RF receiver circuit

    An input bandpass filter reduces the chance of an input overload by a strong signal at another frequency. What is the bandwidth of the signal you want to recover and demodulate? High order filters have steep attenuation curves, which are necessary for selectivity. ak
  15. AnalogKid

    Float Switch for 240V pump using a relay

    No, it won't. It is rated for 100 V, not 240 V, and only 0.5 A, not 2 A. Without some kind of interface device or circuit in between the switch and the pump, the switch will fail quickly. Think solid state relay. ak
  16. AnalogKid

    Float Switch for 240V pump using a relay

    Unless your float switch is unlike most others, there will be no voltage or current "in" the liquid. Usually the switch is immersible but fully insulated. ak
  17. AnalogKid

    Not enough current to trigger relay.

    You said there is not enough current from the phone to drive a relay coil directly. How much current is available? There are other switching devices that can be used. ak
  18. AnalogKid

    Not enough current to trigger relay.

    Restating the problem: 1. Input: Pulsing +12 VDC signal, 2 seconds on, 2 seconds off. 2. Output: Steady +24 VDC switched to a horn. Important question: Is the circuit ground for the phone the same different from the circuit ground for the horn? In other words, does the phone have to be...
  19. AnalogKid

    Float Switch for 240V pump using a relay

    Your relay is DPDT which is more than enough switched contacts. However, it has a 240 VAC coil. Not much current, but still you will have to have 240 VAC on the level switch contacts and the part you have is not rated for that, so the relay you have will not work reliably. What step-down...
  20. AnalogKid

    Float Switch for 240V pump using a relay

    First, you don't say what you did expect, so it's hard to know where to start. Also, the data sheet covers about a dozen different parts. Please give us the exact part number for the relay you have. Without that, there is no way to recommend a circuit. ak
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