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  1. Sunnysky

    Ok I need some switch help

    your LED may only be using a few mA so this is normal for cars with radios that have idle current or alarm security with flashing LEDs . pls verify if you need it. I suggest it is OK.
  2. Sunnysky

    Powering 104 LED's from Molex connector, possible?

    101 ? why not 100 or 104 or why not 200? no big deal to bias 1.
  3. Sunnysky

    Powering 104 LED's from Molex connector, possible?

    Check your supply V and test a few LEDs with 10Ω resistor. Each LED in UB variety >5Cd tend to be 3.1 Nom. +-0.1. Very very few in 5mm are less than 3V, while in >=3W chips, many are 2.9V from lower ESR. 5mm LEDs are mostly ESR of 13 to 15Ω nom, so if you are operating at 12.5V say , then the...
  4. Sunnysky

    Is this heating pad safe?

    is there a lump there? perhaps a ceramic sensor temp that is has a piezo response
  5. Sunnysky

    Is It A Transformer 220vac-110vac ?

    to further protect from line surge voltages of 3kv. add cct breaker and/or CLC line filter from power strip and 500V MOV
  6. Sunnysky

    Electronics Talk - interesting interviews and shows

    I enjoyed reading his book " much ado about ALMOST nothing" Here is his book on IC design 1991 +. https://web.archive.org/web/20071020024358/http://www.arraydesign.com/_count/7MANUAL.PDF
  7. Sunnysky

    Low voltage cutout help

    why are you using a 22V coil from 15.4V nom then dropping with a zener. remove zener. increase Rbe from 1k to 100 k if using same Toshiba Relay at 22V it is 1250 Ohm and will not reliably turn on at 14.4V and you should be using worst case V for reliable operation, assuming everything is...
  8. Sunnysky

    Low voltage cutout help

    next define ideal cut-in /out threshold V and where present chatter occurs. Rcoil =? Change Rbe to >>10k. to drive relay On a bit faster (lower Vce) add R between Vo & Vin+ of 47K or so for hysteresis to prevent chatter.
  9. Sunnysky

    video generator: guidance needed

    Mixing is done in analog. So video capture to analog, software using my link, then convert to hdmi if desired or leave as VGA. Logitech has such software for their cams. or ManyCam works with any video source in windows, mabye others program to interface data stream into subtitles format can be...
  10. Sunnysky

    Home Project wiring help

    most likely you need a 100A DPDT switch with centre off. The motor to bat switches polarity with up/down momentary switches. The wire guage ought to indicate how much current it can carry. with minimal voltage drop. mine is quite heavy duty 16-14AWG but motor surge current is 800%x on...
  11. Sunnysky

    Is It A Transformer 220vac-110vac ?

    that should fix it. WTG dorke. Nameplate indicates transformer can operate with 70W load. That is dictated by temp rise in hotspot and assumes linear resistive load, not a light bulb, nor a motor or a bridge rectifier with large Cap load to a power amp. In these cases derate by 1/3 to 45W. The...
  12. Sunnysky

    Low voltage cutout help

    I am not sure of complete schematic , battery and power load , so I can only guess. There are a few subtle behaviors of relays, comparators and batteries you need to understand regarding hysteresis. A complete schematic would help. Batteries have memory. So when weak and unloaded, the voltage...
  13. Sunnysky

    Low voltage cutout help

    A good relay will have specs that MUST switch ON at 70% of rated voltage ( even if it may switch slowly at 50~60% ) and MUST switch OFF at 10% of rated V ( even though it may chatter off at 25% ) If your supply causes a big drop when turned on , then that is an indication of low State of Charge.
  14. Sunnysky

    video generator: guidance needed

    TRY http://www.videohelp.com/
  15. Sunnysky

    RFID Multi Antenna

    1st essential design is create a spectral loss budget. .. This includes Friis losses , Tx power, Rx threshold,BER requirements, frequency, interference sources and levels.
  16. Sunnysky

    RFID Multi Antenna

    do you have a spectral loss budget?
  17. Sunnysky

    Isolated Grounds

    The encoder signals might need be optoisolated, only if there is high voltage between encoder and mcu. For long distances differential signals may get CM interference, so need to be balanced such as RS485 or a large ferrite balun or twisted pair. It will not work if the optocoupler uses an...
  18. Sunnysky

    RFID Multi Antenna

    Using splitters isolates antennae at a loss in sensitivity. Combining antenna with passive filters requires knowledge of antenna impedance, Smith Charts etc.
  19. Sunnysky

    Power Relay needed

    n
  20. Sunnysky

    Running LED - all LED turn ON when reach the last LED?

    looks like a single LED chaser back and forth. Kitt car era. U3-C & D make an SR flipflop active low input while their outputs enable U3-A&B to steer input negative pulses which get inverted to count up or down.
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