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  1. AnalogKid

    Water level sensor

    Which water level circuit? Schematic? Photo of power supply?
  2. AnalogKid

    How to connect wires to prongs on switches?

    3 common sizes: 0.250", 0.187", and 0.110". The 250 and 187 also are built for two different tab thicknesses *each*, 0.031" and 0.022"(?). The thickness matched up is important - too thick and getting the connector on is nearly impossible; too thin and the connector falls off. They also...
  3. AnalogKid

    5 inch display pcb pinout ?

    Or that connector supports some other feature that your board is restricted from doing. It is a common practice in consumer electronics to have one board serve multiple product configurations. If there are five variations of a product, it is much cheaper to have a few unused holes on all...
  4. AnalogKid

    Making a set of quiz lights

    The lights work out to 100 mA each. I think this can be done electrically with your two switches, two DPDT relays, plus a third switch for reset. Ar electronically with a dual flip flop IC plus some small components, and two transistors to drive the lights. Which are you most comfortable...
  5. AnalogKid

    High-end drones

    Does anyone here know anything a lot about drones? I need a short course on the current state of affairs. This would be for personal use. Question: Do all "decent" or middle/upper class drones need a smart phone and GPS to function? Seems like a lot of complexity just to fly around and...
  6. AnalogKid

    Making a set of quiz lights

    What is your skill set for building a small logic circuit? What are the voltage and wattage ratings of the lights? Do you want to stay with light bulbs or can you change to LEDs? ak
  7. AnalogKid

    Making a set of quiz lights

    You need some kind of cross-connected latching function. With single-pole switches it cannot be done without adding some electronics. Because you have only two stations, this can be done with one chip, 4 diodes, some resistors, and output transistors. How many lights are there? You mentioned...
  8. AnalogKid

    Forgive my ignorance...

    Bob beat me to it. Surface mount parts can be difficult to install, and always are difficult to replace. Yours is exceptionally difficult because of its "power pad" package. The power pad is the large contact area that does not extend to the edge of the package. Without a complete hot air...
  9. AnalogKid

    Amplification to a constant Vpp

    With +/-12 V you can do just about anything. The compressor circuits above will work, but a comparator would be more simple to design and build, and easier to test. ak
  10. AnalogKid

    Amplification to a constant Vpp

    What DC voltages do you have available to power the circuit? ak
  11. AnalogKid

    Amplification to a constant Vpp

    Now that we have more information after 14 posts ... Microphone *amplifier*, not driver. A microphone is a signal source, so it is received/amplified/processed, not driven. Does the output need to be a sine wave, or can it be a square wave that represents accurately the frequency of the...
  12. AnalogKid

    General capacitor question.

    Why not? The lead spacing is very close. If the ESR isn't exactly the same, it probably is close enough to keep the regulator happy, although the radiated interference might increase a tad. ak
  13. AnalogKid

    Circuit Help

    #4 is composed of two components in parallel. When two capacitors are connected in parallel, the total capacitance is the sum of the two. A fixed 60 pF and a variable 0-150 pF combined have an adjustable range from 60 pF (60 + 0) to 210 pF (60 + 150). ak
  14. AnalogKid

    Morse code led without a micro controller

    Working nights at a TV station in the early 70's, I did the paper design for an all-TTL sync generator, then checked it against the National Semi MM5320/21 (probably the part you're referring to). I started a design using a binary counter driving an EEPROM, but about half way through it the...
  15. AnalogKid

    Current sensing circuit help

    120 V / 1.44 M = 83 uA Another real world thing - power transformers designed for a 6 A primary current do not work down to 0.000083 A. That is a 72,000:1 input current range. It's been a while since I've messed with CT's, but I don't know of any 60 Hz core material that can do that. If...
  16. AnalogKid

    LED for electric heater (UK)

    Note - that "all you need" resistor is dissipating 2.4 W at 120, and 4.8 W at 240. For any reliability and safety you'd need a 10 W resistor rating. To meet safety agency rules you need two resistors in series and reinforced insulation around everything. ak
  17. AnalogKid

    LED for electric heater (UK)

    Big, beefy, and expensive, but it certainly will do the job.
  18. AnalogKid

    Measurement device

    Like post #2. There is either a long thin precision glass strip with alternate dark and light stripes, or a hwel with alternate dark and light pie wedges. These go past two optical sensors spaced so that when one is seeing a transition between stripes, the other is in the center of a stripe...
  19. AnalogKid

    Making a set of quiz lights

    Yes, but you have given so little information that it is impossible to say. What do you mean by "stop working"? What kind of switches? Pushbutton? Toggle? Magnetic? How many poles on each switch? Is the circuit AC or DC powered? What kind of light? Please post a schematic of your circuit. ak
  20. AnalogKid

    Info for 2N3904 and 2N3906

    No, no, no. While both of your statements might be true in a very small number of very limited cases, neither is anywhere close to true as a general statement about types of transistors. There is much more to transistor operation than "off" and "on", and it is very bad advice to give to a...
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