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  1. KJ6EAD

    fixing and AVR speaker switch

    I don't suppose there are any manufacturer markings on the switch. It's probably a custom version of the SRBV series by ALPS made for Sony. If it followed the nomenclature pattern of the series, it would be SRBV24xxxx...
  2. KJ6EAD

    What is this component?

    Due to it's appearance, unusual silkscreen label and position near other circuit protection devices, it may be an avalanche diode. You can get the whole board online for $75.
  3. KJ6EAD

    horizonatl line

    There's probably no Radio Shack store in Badin, but RS Components distributes there.
  4. KJ6EAD

    How long will AA batteries power my project

    The 7-segment displays may use almost as much as the seconds LEDs if they have 2 LEDs per segment and run at 20mA. The minutes display has an average of 4.8 segments lit, the 10 minute display averages 4.5 segments lit, etc.
  5. KJ6EAD

    MAKE: Electronics Ex. 10 Help Needed

    The book indicates a 12V supply and the component values are consistent with that.
  6. KJ6EAD

    MAKE: Electronics Ex. 10 Help Needed

    I thought you guys liked 15 Megapixel images so you could zoom in and see everything in clear detail. :D
  7. KJ6EAD

    Boring question for you guys...chargers and amperage

    If they're both USB connectors, they're capable of at least 500mA and probably interchangeable. No harm can come from trying. The worst that can happen is the battery charge circuit in a device won't allow charging because it doesn't see the right reference voltage on the data pins.
  8. KJ6EAD

    Boring question for you guys...chargers and amperage

    The answer is maybe. If the output connectors are some type of USB, then the voltages and pin connections will be the same but the device that normally uses the higher amperage charger may not be satisfied with the smaller capacity charger. Some manufacturers like to do odd things with the two...
  9. KJ6EAD

    horizonatl line

    If it's a CRT (TV tube) and it's displaying a single bright horizontal line in the center of the tube, your vertical deflection circuit has failed. The most likely cause is a dried out electrolytic capacitor.
  10. KJ6EAD

    where to find bright SMD LEDs

    These are the best. http://www.cree.com/products/pdf/ProductBriefs/SMD%20LEDs.pdf http://www.nichia.co.jp/en/product/led.html To compare the luminosity of one LED to another, convert to lumens. Here's a calculator: http://www.ohmslawcalculator.com/mcd_to_lumens.php
  11. KJ6EAD

    What Resistors should I have

    Get at least the E12 series of resistor values and if possible the E24 series. http://www.logwell.com/tech/components/resistor_values.html E12 resistor set: http://www.jaycar.com.au/productView.asp?ID=RR1697&form=CAT2&SUBCATID=968#1 E24 (almost) resistor set...
  12. KJ6EAD

    Anyone played with rubidium frequency standards?

    Dave Jones got into one a bit on his EEVblog (episodes #235-6).
  13. KJ6EAD

    Powering multiple circuits and a motor with Batteries

    A 1W amplifier and a motor that probably dissipates around 0.6W or so means your batteries would need to have around 2Wh of capacity for every hour of run time. 4 alkaline D cells would probably run for 3 hours or more, smaller batteries less. Once you have everything assembled, you can measure...
  14. KJ6EAD

    lightning arrester @ base station

    A lightning arrestor is made with a gas discharge tube. The low voltage of the RF signal isn't nearly enough to ionize the gas, providing a path to ground. Lightning easily ionizes the gas.
  15. KJ6EAD

    9 volt usb charger

    Adafruit has been selling the Mintyboost kit for a couple of years. It uses 2 AA batteries which works better and is more economical than a 9V battery. http://www.adafruit.com/products/14
  16. KJ6EAD

    Buzzer as vibration unit?

    You should be able to program your microcontroller to play a WAV file on an analog port. If not, any oscillator circuit that would run on your available voltage should work.
  17. KJ6EAD

    Buzzer as vibration unit?

    Yes if it's a big AC magnetic type, but the common small piezo devices would not be a good choice. Perhaps a very small speaker (~30mm) such as are used in lightweight headphones driven at a low frequency would work. Search online for haptic feedback transducers for more ideas.
  18. KJ6EAD

    Need help in LED lighting

    LEDs have low reverse breakdown voltages and motors throw big reverse voltage spikes on the line when they're switched off and their magnetic field collapses. Get a new LED and put a power diode such as a 1N4007 in reverse parallel with the LED/resistor combination. This will snub the reverse...
  19. KJ6EAD

    Buzzer as vibration unit?

    If you can get a scrap cell phone, you can scavenge the vibrator from it.
  20. KJ6EAD

    Mini Radio Beacon Circuit

    Google telemetry transmitters.
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