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  1. Sunnysky

    Creating logic AND gate with 2N222 Transistor

    in the 1st circuit, a Large 100k~1MΩ resistor from base to ground (V-), shunts stray e-field leakage and allows it turn off LED. Otherwise , waving hand near circuit makes it brighter when both sw. off. Put on both bases to V- for best results.
  2. Sunnysky

    Need to know about this part

    try a 12Vac center tap ~5 VA transformer.
  3. Sunnysky

    Help building a crossover

    There are a few more critical details. The cap needs to be a high quality non-polarized cap. A non-polar electrolytic may work, but polypropylene is much better (PP) http://www.digikey.ca/product-detail/en/nichicon/EXH2E705HRPT/493-13830-ND/4694507 The inductor should not saturate with a...
  4. Sunnysky

    would like to build a radio transmitter

    Do you really want to reinvent the wheel? or use an IC to transmit , then define what is transmitting, receiving ,bandwidth and distance. or buy a kit or pre-made Tx, Rx?
  5. Sunnysky

    What fuse would a need?

    If LED spec is 6A max (14.5V) then use a slightly bigger fuse. Thats a lot of LEDs! cigarette lighters are usually 15A fuses
  6. Sunnysky

    Building a 1 kW automotive voltage regulator

    LDO? No, not , never. First understand how an alternator works by amplifying field current with moving rotor and then see how voltage ...regulator controls field current to correct the output rectified voltage. Then review my MOT IC link and @debe's suggestion until you understand how both...
  7. Sunnysky

    Hantek 5102

    is this a procedural question on DSO? I rarely do, but when in doubt RTFM read the fine manual. ...snip Push the MEASURE button to perform auto measurements. There are 32 types of measurements and up to 8 can be displayed at a time. Turn the V0 knob to select an unspecified option. Press V0 or...
  8. Sunnysky

    Sony TAF40 LED Repair

    pin 9 is V+=13V pin8 is rectified sig. input., compare all pins. http://www.hifiengine.com/hfe_downloads/index.php?sony/sony_ta-f40_service.pdf
  9. Sunnysky

    OHAUS replacement LCD

    did you ask ohaus? http://us.ohaus.com/en-us/educators
  10. Sunnysky

    LED monitor using phototransistor

    PD's are broad spectrum unless they are for IR with dyalight blocking black lens. The below link shows the common emitter cct which inverts voltage by current amplification. Photons of LED light should saturate the collecter R of 10k for a logic 1 with the absence of light being pulled up by...
  11. Sunnysky

    Power Relay needed

    When you define that it must be self powered and the lack of indication implies power failure, and you want high accuracy, with LED indication at a voltage above 1.5V which is below where LEDs turn on bright, you must realize you have defined a very restrictive set of requirements. For $150...
  12. Sunnysky

    Building a 1 kW automotive voltage regulator

    as in any design, start with a list of specs.; Vin min-max Vout tolerance, load regulation, input regulation. Load type. Start surge current limit. efficiency min. Experience, budget, timeline. Is this intended to be just the regulator inside/for the alternator? Then it is different...
  13. Sunnysky

    Drift issue in capacitance measurement, why?

    it appears to me your gain is max but temp compensation is 0 . like SF{X,Y}= FFH, SFTC{X,Y} = 7FH, and GAIN = 7FH. my setting are SF{X,Y}=FFH, GAIN= 7FH, but SFTC{X,Y}=00, so the gain is not max gain. All the other registers are set 00H.
  14. Sunnysky

    Drift issue in capacitance measurement, why?

    It seems the micromotion of the socket is a major source of drift errors. So eliminate it. Perhaps Swiss style circular sockets will be more stable with fixed outer socket and circular spring contact inside rather than parallel contacts in IC socket which can move, while soldered connections...
  15. Sunnysky

    30 leds blinking with music (not vumeter)

    NO you totally misunderstand. Use LEDs and this board, no load on preamp
  16. Sunnysky

    30 leds blinking with music (not vumeter)

    https://www.amazon.ca/Velleman-Low-Voltage-Light-Organ/dp/B001IRMDOK?ie=UTF8&SubscriptionId=AKIAIKBZ7IH7LXTW3ARA&ascsubtag=578c395948308f1e74f05ddf&camp=2025&creative=165953&creativeASIN=B001IRMDOK&linkCode=xm2&tag=stuccu-20
  17. Sunnysky

    auto resetting timer 110v a/c

    all he needs is a float switch with a timer like a CD4060 with a relay and transistor and 12VDc and a perf board with magnet wire http://www.electronicecircuits.com/electronic-circuits/cd4060-timer-circuit-1-minute-to-2-hours
  18. Sunnysky

    auto resetting timer 110v a/c

    usually a float switch senses when sump pumps cut out. I had a rental property vacated that sprung a leak (cold water pipe solder separated) in winter and the house would have flooded except the sump pump in the lowest corner prevented major damage by running, which caused me to rip out...
  19. Sunnysky

    "Good" DMMs with bar-graphs - crippled by design?

    I recall my Fluke DMM has a fast dot... bar graph display, but still not as fast as an analog meter.
  20. Sunnysky

    auto resetting timer 110v a/c

    http://www.homedepot.com/p/Defiant-20-Amp-60-Minute-In-Wall-Spring-wound-Timer-with-White-and-Almond-Wall-Plate-49823/204209953
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