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  1. Externet

    Car Cd Player AUX input

    Better do not touch nor tap onto the CD connector at all. Obtain the schematic to select where to feed the aux input. If no schematic; look at the integrated circuits data sheets. You may find which is the audio path management. Better using the AM radio path, or perhaps the IC has an unused...
  2. Externet

    Power powerwheels

    What gearing down does is increase torque, and powering that two+ horsepower 100V motor with 6-12V, the power draw will be around a tenth. Perhaps you have overseen that keeping the original motors and replace/using a battery of the same voltage with larger capability (motorcycle type) would...
  3. Externet

    Add line out to speaker-damaged Garmin GPS?

    It is worth replacing and restoring the speaker functionality for pennies : ----> https://www.aliexpress.com/wholesale?SearchText=gps+speaker&opensearch=true
  4. Externet

    Power powerwheels

    Seriously consider your mechanics after more seriously considering the safety of your 5 year old...
  5. Externet

    Display Lens Source

    Look for clear-colored plastic 'dividers' for folders at the office supply place. Or, If you find the wanted thickness in clear acrylic/plexiglas, mix fountain pen ink with clear coat and spray.
  6. Externet

    Noise reduction .

    Use an audio switch integrated circuit built dedicated for that. Most feature fade-out/fade-in and zero crossing. This is in a hard-to-handle package, but there is others : ----> https://datasheets.maximintegrated.com/en/ds/MAX4910-MAX4912.pdf
  7. Externet

    Electret headphones amplifier

    An amplifier ? A transformer is a voltage amplifier. You do not need a power amplifier. That is already in your 'stereo' to feed the transformer. The transformer alone will nearly 'match' the impedance to your earphone needs.
  8. Externet

    Motion sensor that senses motion not the change in temp

    ---->...
  9. Externet

    Electret headphones amplifier

    No place for 'bridges' here. Look in your junk box for a 230V to 3, 5, 6 V linear adapter and canibalize the transformer alone. Feed audio into the secondary and the earphone to the primary. If satisfactory, repeat for the other channel.
  10. Externet

    Anyone familiar with pendulum clock mechanisms ?

    Thank you. Unreliable self-start... :( hmmm In need of oscillatory mechanisms, ordered a couple as they are cheap, and will evaluate when arrive. As will not need a pendulum, there may be enough push to self start. Will see. Did not find a AA operated mechanical metronome or something...
  11. Externet

    Anyone familiar with pendulum clock mechanisms ?

    Hi. Trying to find if these common AA operated mechanisms are self-starting or need a first swing by hand to start. Or the pendulum mechanism alone :
  12. Externet

    LM2917

    Better hook your circuit to the Vss signal for speedometer instead of tampering with wheel sensors, that may pose a dangerous situation as they are part of anti-lock brakes circuitry and doubt you should ground a floating balanced signal. I used the LM2917 on Vss to implement a TCC relay...
  13. Externet

    Rechargeable LED pairs - how do these work?

    Are you sure ? (+)-----R------led------(-) (+)-----R------led------(-) (+)-----R------led------(-) (+)-----R------0Ω------(-) (+)-----R------led------(-) (+)-----R------led------(-) (+)-----R--------led--------led--------led-------0Ω-------led-------led------(-) Only here...
  14. Externet

    Replace 9Volt Battery with Solar Panel

    One of these next to each sensor wired to its rechargeable 9V takes care or the task : ----> https://www.radioshack.com/products/radioshack-1w-solar-panel-9v I was not implying running wires to all sensors from a single panel...
  15. Externet

    Replace 9Volt Battery with Solar Panel

    Hey ! By 80 they take our driving licenses away; but by 60 they should have taken your ladder away ! I would use a rechargeable 9V and connect directly a panel that supplies 9-10V.
  16. Externet

    Darlington transistor suggestion ?

    :) Nice find... question... what is called logic level ? Are they generalizing ? Is it 5V logic; 3.3V logic; 2.5V... logic level ? Is it left to guessing for their product ? Shouldn't it be specified like "3.3V logic" ? Which brings another... what about level translator ICs...
  17. Externet

    Darlington transistor suggestion ?

    Would like to know who comes up with this trifle of which is upper case, often misused by even instructors... When Gain.dc or Gain.ac would say it... Well, I was after around 0.3Vce sat conducting less than 0.5A to energize a circuit powered by a nearly discharged lithium cell from about 10...
  18. Externet

    Darlington transistor suggestion ?

    Thanks. There is only 2.5V, but enough mA for the base current. Will look into a higher hfe transistor.
  19. Externet

    Darlington transistor suggestion ?

    Hi. Looking for the least Vce at saturation for power switching, will conduct half Ampere Ic maximum. 12Vce maximum, PNP or NPN. Have a bunch of old non-convincing TIP121. Cannot use a mosfet; gate voltage too low to drive it.
  20. Externet

    Considerations to make this contraption work ?

    Thank you. I see that goof now. Better use another transistor to discharge C trough Rd. The 'on when dark' works dusk-to-dawn, keeping the circuit on all night.
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