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  1. AnalogKid

    lm386 and electret microphone problem

    There are a lot of low cost modules from china based on the 386 as a mic preamp. Low parts count and indestructable, but not enough gain, high distortion and noise, and not enough gain to go from mic level to 8-ohm speaker drive. Did I mention the gain? ak
  2. AnalogKid

    Need help using phonograph as guitar amplifier

    If you are using the phono input, the frequency response will be terrible. The phono input has RIAA equalization applied to the signal, basically turning the high frequencies down by up to 40 dB compared to the lowest frequencies. With a schematic and a photo we probably can figure out which...
  3. AnalogKid

    Setting the I2C address - Funduino LCM1602 I2C Backpack

    What probably is the case is that the three underside components are either pull up or pull down resistors for the three address pins, and the jumpers pull the pins to the opposite rail. This is important because the direction the jumpers pull the pins sets the logic polarity. ak
  4. AnalogKid

    Setting the I2C address - Funduino LCM1602 I2C Backpack

    If you look at the traces on the pc board, you see that they go to pins 1, 2, and 3 of a PCF8574. This is an I2C I/O expander. The datasheet shows that it has three address pins (1, 2, and 3), and how they fit into the I2C address space. The datasheet does not mention internal pull up or pull...
  5. AnalogKid

    Can I Change Transformer step down with stavolt/stabilizer

    Grammar is fine, but a 1600 W blender - ?!? anyway, what is the make/model/part number of the transformer? ak
  6. AnalogKid

    Connector advice required.

    A 33 W fan in a pc? Did it come with ear plugs?
  7. AnalogKid

    Connector advice required.

    Probably 24 V fan.
  8. AnalogKid

    Can anyone Identify this component?

    With both a + sign and a beveled corner, that's got to be a tantalum cap. ak
  9. AnalogKid

    Camera Cycle Circuit

    Getting closer. The problem for accurate/repeatable positioning is that what you describe wil be running open loop. There is no guarantee that the camera will be moving at exactly the same speed every cycle, so a constant pan or tilt time will not end at the same angle every time. There are...
  10. AnalogKid

    Camera Cycle Circuit

    It sounds line the overall motion is describing a square or rectangle, up-over-down-back. 1. How long would each of the four operating states be active? 2. Any dead time between states? 3. What happens if a state is active so long that the pan/tilt head runs out of motion range? Will this...
  11. AnalogKid

    Parallel power supplies?

    Depends on the supplies, but the diodes help a lot. A problem with them is the negative temperature coefficient of Vf. Whichever diode starts out conducting more current heats up more, it's Vf decreases, and it becomes even harder for the other supply's diode to conduct. Some of this effect...
  12. AnalogKid

    Can anyone Identify this component?

    The date codes on the chips are 1986 and the cap logo looks like Panasonic's old one, so if someone has a *really* deep library... ak
  13. AnalogKid

    indoor localisation for minute positional changes of moving objects

    Think about football. Televised professional American football. The system that superimposes the line of scrimmage and the down line relies on three rotary encoders per stationary camera. The encoders send back signals related to rotation, tilt, and zoom lens setting, and a gigantic buttload...
  14. AnalogKid

    Have you seen one of these and how can I make it work.

    Before the days of circuit simulation software, circuits were debugged and tuned by manual calculation and trial and error. If for example you wanted to see the tradeoffs of stability versus bandwidth in an opamp circuit, you could spend all day soldering in and then unsoldering a dozen...
  15. AnalogKid

    12V Battery on a 230V/50Hz Pump

    Many of the answers are under your control. If you buy a 12 V DC pump and use a 12 V DC battery, no conversion is necessary. If it is a 220 VAC pump, then you need an inverter. Figure 80% efficiency, so 20% of your battery power goes up in heat. Step 1, what are the water-moving requiements...
  16. AnalogKid

    Hovering Drone....W/Kg Calculation.....

    ak: Nope, a boat doesn't hover. It is propelled to the surface of the water by gravity, and it requires energy to keep it there. BobK: Really? Where does that energy come from? If you believe this, then you must believe in free energy. Really? *must*??? Quite a leap of...
  17. AnalogKid

    Hovering Drone....W/Kg Calculation.....

    Nope, a boat doesn't hover. It is propelled to the surface of the water by gravity, and it requires energy to keep it there. ak
  18. AnalogKid

    Just how

    Good analog-y. ak
  19. AnalogKid

    Design of isolated buck converter

    What are the isolation requirements? Does this circuit need to pass safety certs? Also, is there a reason to go through a design process when many power supply manufacturers make a suitable device? ak
  20. AnalogKid

    will this really give me a triangular wave?

    Ask a decent question, get a decent answer. ak
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