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  1. Sunnysky

    Power Relay needed

    I would think Digikey is a better place to choose parts and deliver same day.
  2. Sunnysky

    Creating logic AND gate with 2N222 Transistor

    not relevant.. also Vout is not affected due to saturation and gain. This question shows you thoroughly understand EMC and can read schematics for transistor ccts and estimate voltages, tests your experience on floating inputs, and shows you understand about noise immunity what it means, for...
  3. Sunnysky

    Power Relay needed

    Choose ultrabright LED indicator so you can conserve battery >10Cd @ 20mA, so use 2mA , that is 1000 mcd and plenty bright. cost 0.25 Choose convenient battery 4x AA or 9V Alkaline. Choose low voltage comparator , any Choose low voltage 3 or 3,3 V LDO. , any Choose R ratio with high value...
  4. Sunnysky

    Creating logic AND gate with 2N222 Transistor

    Nobody got close to the correct answer. The floating input voltage threshold for TTL in every generation is two base-emitter diode drops or 0.65x2 =1.3V. The voltage needed to pull the floating input down to cause an output transition is about 0.1~0.2V. so 1.2 ±0.1 The same "rated "...
  5. Sunnysky

    Cheapest way to get data from multiple(100s) of sensors?

    recall original question? "I plan to have 100s of Reflective IR Sensors and want to be able to read from all" I wonder how much thought has gone into what objects needed to be detected and ignored. what is the medium? and what objects? and what optical SNR is needed vs range? apertures on a...
  6. Sunnysky

    How to control the speed of a 24vdc pump from circulating water temperature?

    I am curious about the pump's hysteresis for %pwm for 1) start 2) stop 3) min needed for acceptable quiet and adequate flow when max heat flow is desired 4) any resonant acoustic speeds in between.
  7. Sunnysky

    Need to know about this part

    My suggestion is use a wallwort and feed DC onto the board
  8. Sunnysky

    Need to know about this part

    yes
  9. Sunnysky

    Understanding The Following Circuit

    triode mode= ohmbic= linear mode. i.e. voltage controlled resistor
  10. Sunnysky

    How to control the speed of a 24vdc pump from circulating water temperature?

    Thanks so water control only. An analog temp Voltage and PWM voltage controlled power to pump will perform as well as you define it which depends alot on water radiator efficiency and flow rate. Tcut-off for pump. .. I suggest 20'C Tcut-in for pump at slow speed... perhaps 25'C Tmax for water...
  11. Sunnysky

    Need to know about this part

    Can you remove transformer and replace with any 12Vdc supply to secondary pins? with correct polarity! with regards to caps.
  12. Sunnysky

    Understanding The Following Circuit

    weird circuit. O/P is actually an I/P. The function may be to protect Vin(-) pin2 and FET clamps it to Vin(+) if external 1M point goes more negative than Vin(+) reference. , otherwise FET is off. input bias currents will deterimine actual triode operation. with no current on 1M
  13. Sunnysky

    Air Compressor Controller

    de morgan's law states inverting all inputs and output inverts function from/to AND/OR If contact is normally closed, call that "0" , so all inputs in series will be ANDed when output is Closed="0". Active low means negative logic if contacts are looped to ground. If all contacts are connected...
  14. Sunnysky

    Replace IGBTs FF200R12KS4 with FF300R12KS

    someone who knows how to replace correctly and test
  15. Sunnysky

    Replace IGBTs FF200R12KS4 with FF300R12KS

    it depends. if in doubt, get help.
  16. Sunnysky

    How to control the speed of a 24vdc pump from circulating water temperature?

    I must have missed where he indicated there was a hot water valve thermostatic regulator. If the intent is to prevent boiling and/or excessive pump noise/speed then when the thermostat indicates off, the excess water heat must be dumped to prevent boiling with a recirc. valve and/or flame...
  17. Sunnysky

    Replace IGBTs FF200R12KS4 with FF300R12KS

    It is worth trying and compare device temps to ensure operating <<=85'C
  18. Sunnysky

    Power Relay needed

    no. a fixed separate bat. will control LED current independant of 0-28V
  19. Sunnysky

    Power Relay needed

    No For same reason. Reg will not operate at low Vin. Why complicate the design, when an infrequently used indicator will not drain a battery much? Your high level requirements or objectives are now unclear.
  20. Sunnysky

    How to control the speed of a 24vdc pump from circulating water temperature?

    If you dippped in room temp water and could see light turn off and on with 2 deg shift, then it works. 70'C indicates far too insensitive. Remember you are trying to detect air temp. But if you also want to detect water temp to disable pump, then that is a good idea to add.
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