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  1. AnalogKid

    Activating a pump based on water flow

    Can you measure the resistance of the relay coil? Photo? ak
  2. AnalogKid

    Activating a pump based on water flow

    I'm not a huge 555 fan, but its big fat output stage can drive small loads directly. Relay details? ak
  3. AnalogKid

    Activating a pump based on water flow

    Yes. What you want is called a retriggerable monostable, or missing-pulse detector. As long as pulses happen often enough, the output is in one state. When pulses stop for a minimum period (the detection window), the output goes to the other state. This is the circuit that takes fan tach...
  4. AnalogKid

    Trumps solar wall, forget politics we should just build the thing

    Sweet. ak
  5. AnalogKid

    Call or Signal Box for Warehouse

    The nice thing about this circuit is that it can run on anything. As long as the light, bell, relay coil, and relay contacts all are rated for the same operating voltage, it can be 5Vdc, 240 Vac, or whatever. IF the DPST customer switch is a problem AND IF the circuit is running on a DC...
  6. AnalogKid

    Trumps solar wall, forget politics we should just build the thing

    I disagree. Neither the government of Mexico, the drug cartels, nor the fruit pickers give a rats ass about a physical, financial, or political takeover of the United States government. In fact, they are desperate for our government to stay intact. Regardless of the blatant and bizarre misuse...
  7. AnalogKid

    Relay

    The circuit will work better if you swap the two comparator inputs (to change the output logic polarity to go high when you want the motor to run) change the transistor to an NPN (with base resistor) or N-channel MOSFET (2N7000, 7002). The gate or emitter goes to GND and the collector or drain...
  8. AnalogKid

    Trumps solar wall, forget politics we should just build the thing

    So ... The real news is that you are a fraud whining about fake news. Actually, that's not news. ak
  9. AnalogKid

    Electro Pounce Machine

    Looks like a high voltage transformer with a capacitor in series to limit the current once the arc has been struck. Transformer construction and capacitor type are very similar to the innards of my old electrostatic air cleaner. That one produced around 7 kV. ak
  10. AnalogKid

    12v bar graph help

    Then show us your schematic so we can review it. ak
  11. AnalogKid

    Trumps solar wall, forget politics we should just build the thing

    Look behind you. This was stupid a loooong time ago. Since English is not your first language, let me help you out by explaining something. "Fake news" is not a thing. It is a meaningless phrase of two unrelated words, like "apple submarine". The facts in a news story can be incorrect, but...
  12. AnalogKid

    Trumps solar wall, forget politics we should just build the thing

    Heritage Foundation = Old Testament only.
  13. AnalogKid

    Trumps solar wall, forget politics we should just build the thing

    If that is a serious question, then - no. Air conditioners are rated in tons. A refrigeration ton is the amount of heat transfer needed to melt one ton of ice in 24 hours. Even if the cooling system could move enough heat in 16 hours to cool the room for 8 hours (and, it can't), at a working...
  14. AnalogKid

    Trumps solar wall, forget politics we should just build the thing

    No, they don't. The above quote is a perfect example of that. ak
  15. AnalogKid

    Calculate Op Amp Gain

    Referring to the original schematic, the opamp voltage gain from pin 3 to pin 6 is as in equation A, with a series feedback resistance of (R1+R2). Pin 6 is a zero-ohm point at voltage (Vin times the gain). Pin 3 is a zero-ohm point at voltage Vin, driven there by the opamp's closed loop. So...
  16. AnalogKid

    Boost AC circuit

    Something with active power factor correction, sometimes called a universal input. Better than autoranging, these will run on any AC input voltage between 85 and 260 Vrms. -ish - the exact range varies with manufacturer. A true industrial-grade multi hundred watt unit will cost $1-$2 per watt...
  17. AnalogKid

    What transformer is this?

    How do you know it is a transformer? ak
  18. AnalogKid

    Boost AC circuit

    Another strategy: a DC powered air pump motor. A universal input AC/DC power supply would ride through brownout sags down to 90 Vrms. And, you could add a battery stack with simple diode OR-ing for deep dips. ak
  19. AnalogKid

    Power supply rectification

    You must post the schematic so we can see the circuit. ak
  20. AnalogKid

    Optoisolator Circuit

    Can't draw a sch right now. 2N7000 or 7002 MOSFET: Sensor output to gate Source to GND Drain to 6N137 cathode 6N137 anode to 220 ohm resistor. 220 ohm resistor to +5 V. 2N4401, 3904, 2222 Bipolar transistor: Sensor output to 1K resistor 1K resistor to NPN transistor base Transistor emitter to...
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