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  1. BobK

    How to make a day/night cycle controller

    Okay, you did say programmable with knobs, but as long as that is what you want, go for it. What I described could be done with 1 tiny chip, 2 transistors, and few resistors and capacitors. Bob
  2. BobK

    How to make a day/night cycle controller

    You mentioned knobs. You still have not told us what the kniobs do. You also have not told us how the LEDs behave. Here is an example of how you might specify the behavior in a way that might help. The white and blue LED alternate in a day night cycle. In the middle of the day period, the...
  3. BobK

    How to make a day/night cycle controller

    What do the knob controls do? What kind of LEDs? 20 mA indicator LEDs or 100W COB modules are slightly different. Bob
  4. BobK

    Finding a piece like this?

    Or, if you are going to use this in a microcontroller or microprocessor based device, use a full color graphics display and have all the flexibility you want. Bob
  5. BobK

    Finding a piece like this?

    And be aware, you will need a display driver IC or microcontroller with built in LCD display driver to run these things. They bring out each segment, and you need an alternating voltage to drive each one. Not nearly as easy to use as LED displays. If power is not a problem, you are probably...
  6. BobK

    Fast Switching Relay for High frequency Signals

    I am still trying to figure out why there is 190 to 450 kHz coming out of a PA amplifier. Bob
  7. BobK

    UM66 is not giving full tone

    In the US, there is typically a 12V transformer attached to the electric panel for the doorbell circuit. Bob
  8. BobK

    Integrated random voice switch

    You wont find all of this in one or even a combination of commercially available devices. What is your experience level at building your own circuits, if any? Bob
  9. BobK

    Simple NiMH Charging Circuit and Resistance

    Trickle charged with no termination condition, relying on it eventually getting dark and discharging the battery. Bob
  10. BobK

    RCA out to 1/8" headphones on Vizio smart TV - clipping/distortion?

    Here is one that explicitly says it can be used with line level outputs. Not endorsing it, because I have not direct knowledge, but it should work. https://www.amazon.com/dp/B01CPUVPEM/ref=psdc_13880161_t3_B01BW8TDTW Bob
  11. BobK

    RCA out to 1/8" headphones on Vizio smart TV - clipping/distortion?

    Actually, you managed to pick about the only amplifier that will not work. If you read the product description, that amp is explicitly designed to look like a headphone to the device outputting the sound. Consequently it has a low input impedance of 16Ω, which is exactly what is causing the...
  12. BobK

    Help how to calculate a LED wall 10 M2

    Do you have any idea how much light that will put out? Are you trying to blind someone? A wall with 8000W of LED lighting is ridiculous. 80W would light any reasonable sized room brightly. 800W would be sunglasses time. 8000W -- forget it. Edit to add: A typical room in my house is lit...
  13. BobK

    100K capacitor = 100pf?

    All my 10pF caps are marked 10 not 100. All under 100 are marked with pF in 2 digits. All my 100pF ones are marked 101. So 100 and 101 might very well both mean 100pF. bob
  14. BobK

    Ozone generator unable to reset"Service light"

    India Pale Ale? Bob
  15. BobK

    Li ion battery charger, adapting power bank

    The current used to charge a battery is proportional to it's capacity. If you try to charge an 800maH battery with a charger designed for the 2000 maH battery, it will give it 2.5 times the correct charging current. If you really knew what you were doing, you might be able to take the little...
  16. BobK

    +DC_out_rtn, what does this mean..

    If you want to power to come on whenever the power supply is powered, short it to the return (ground.) The pwr_ok is an output that indicates the supply is regulating properly. You don't have to do anything with it. It only works correctly if you are drawing at least 5W of power. Bob
  17. BobK

    Wiring 5v to a 12v powersupply

    That calculator shows that any of those wire gauges meet your specification for less than a 2% drop in voltage over 1 foot. In other words, 22 gauge is sufficient, and the wires could be extended to nearly 3 feet before they would drop 2% of your 12V which is 0.24V. Bob
  18. BobK

    Simple NiMH Charging Circuit and Resistance

    How do you figure that? Not even considering the 0.7V drop of the diode or the 2.4V drop of the batteries: I = V / R = 5 / 25 = 0.2 = 200mA. The correct calculation is: V = 5 - 2.4 - 0.7 = 1.9 R = V / I = 1.9 / 0.250 = 7.6Ω But a trickle charge for NiMH should actually be 0.05C or 125mA...
  19. BobK

    Making a high speed pulser

    Or, just to tweak a couple of forum mrmbers, how about a chain of 1500 555s? Bob
  20. BobK

    Making a high speed pulser

    Have you thought about a schmitt trigger, resistor and capacitor for each delay unit? Bob
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