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  1. AnalogKid

    Output Voltage Selector

    Alec, you want both sources tied together in the middle. What you show has the two internal diodes in series, but one has to be reversed with respect to the other. ak
  2. AnalogKid

    Call Progress tone

    Dial tone, busy tone, progress tones - does your feedback tone have to be anything specific, or just "phone-company-sounding? One opamp or transistor can make a respectable sinewave as a phase-shift oscillator, so one quad opamp can generate two tones, sum them together, gate them on and off...
  3. AnalogKid

    2W Voltage amplifier help

    With a 50 ohm output resistor, 50 ohm load, and 10 V at the load, that's +20 V @ 200 mA worst case output, requiring a 24 V positive power source. There are many small DC/DC converter modules that will turn +24 V into -5 V for the negative rail. If you back off the output requirements to a 10...
  4. AnalogKid

    2W Voltage amplifier help

    Is the 1 V signal continually varying between 0 V and 1 V, and 10,000 V/s is the maximum rate of change as it varies, or does it go up to 1 V, sit there for a while, then go back down to 0 V? What goes up... Think about a 50 ohm output resistor for source-terminating a coax cable. It doubles...
  5. AnalogKid

    2W Voltage amplifier help

    no and yes. As a blanket statement, audio devices will not be suitable for your project. A small percentage are DC coupled, but they use a low frequency servo amplifier to achieve this, and it assumes that the average value of the input waveform is zero. So, audio = bad. a 100 us risetime...
  6. AnalogKid

    2W Voltage amplifier help

    There are thousands of circuits and products that will amplify an analog signal when powered from +/-12 V. A clean 10 kHz square wave or pulse requires a signal bandwidth much greater that the standard audio 20 kHz. Depending on how close to 0V the output must be, you might be able to get away...
  7. AnalogKid

    audio speed in mobile communication

    I don't know what you are asking about. Wikipedia has several pages on how phones work. Are you asking about how phones work electrically, or why the audio bandwidth is so narrow, or something else? ak
  8. AnalogKid

    identify temperature IC

    There are thermometer (temperature transducer or sensor) IC's and there are thermostat ICs. All of the sensor's I've seen have a positive output coefficient - voltage goes up when temperature goes up. Thermostat ICs do not make a linear output. The output is a digital logic low or high, and...
  9. AnalogKid

    2W Voltage amplifier help

    A couple of things. 5 V across 50 ohms is 0.5 W, not 2 W, The output current return is through R2 (which is shorted ont on your drawing), so the output power will be nowhere near 0.5 W, let alone 2 W. For the circuit to work the way you want, the system ground needs to be a direct connection...
  10. AnalogKid

    Is this actuator really 12VDC? Could it be 24V?

    Manufacturer, part number, and data sheet do. ak
  11. AnalogKid

    Woo Woo need a diode ?

    What you are trying to do will not and cannot work. While there is such a thing as a scalar field, it is not what you think. https://en.wikipedia.org/wiki/Scalar_field In all of electronics, there is no such thing as a mobius coil. Simply bending a piece of wire into a figure-8 is not what...
  12. AnalogKid

    How does this work?

    Does it ever occur to you, for just one millisecond, to disagree with someone respectfully? Do you even know how? ak
  13. AnalogKid

    audio speed in mobile communication

    "Audio speed" is not a standard term. If you mean audio bandwidth, the range of frequencies in audio, then a common bandwidth is 300 Hz to 3 kHz or 4 kHz. ak
  14. AnalogKid

    Automatic Battery/External Power supply switch circuit

    That clears up several things. The most simple way to automatically switch from battery to external DC power is not to switch at all. Connect the load to the XUMA output only, and connect the external DC to the XUMA input only. This works if the load on the battery is not pushing its limits...
  15. AnalogKid

    Automatic Battery/External Power supply switch circuit

    Then it is even more important that the drawing capture the return connection(s). Does it have 3 or 4 contacts/wires? ak
  16. AnalogKid

    Automatic Battery/External Power supply switch circuit

    No. Among other things, your drawing has no connection to the DC connector center pin, and no GND connection to the Rpi. That is what you drawing shows, which is why it is not correct. To start with, a battery does not have an "in" and an "out" terminal, or a "charging input". It has a...
  17. AnalogKid

    Automatic Battery/External Power supply switch circuit

    The switching jack is the most simple approach, but your wiring is incorrect. If the AC adapter center pin is GND, or - as indicated on your drawing, the the center pin, battery negative terminal, and Rpi GND input all are tied together. None of those connections is switched. The battery +...
  18. AnalogKid

    Oscillator or Not?

    My point is - If the position you *choose* to put into words is this: "The purpose of this experiment is to determine if there are any negative affects on seeds..." (emphasis mine) rather than this: The purpose of this experiment is to determine if there are any affects on seeds... then the...
  19. AnalogKid

    Zeroing out a LM317 reference voltage with a zener - PSU build

    Yes. Remember to adjust R1 to keep the zener current within its range. ak
  20. AnalogKid

    Oscillator or Not?

    Edison presided over a patent production line. He had teams of assistants and researchers doing the grunt work, often substituting tons of cheap labor for some actual science. I got the 200 number from two Edison museum curators independently, one in NJ and one in FL. Most people are more...
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