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  1. BobK

    Baseball Scoreboard

    Hi, welcome to the forum. Yes, it is totally doable. There are wireless remotes that have various number of channels. You would need 2 indicators for strikes, 3 for balls, and 2 for outs, so, 7 channels in all. Here is an example...
  2. BobK

    design of RTOS using few features

    Yes, you can make a mult-tasking kernel without other RTOS features. I made one for PIC16 series that featured only cooperative multitasking with round robin scheduling and a single byte of flags for synchronization. Bob
  3. BobK

    SMD 0805 capacitors

    With something to compare and that large difference, you are right, it has identified a problem capacitor. Bob
  4. BobK

    SMD 0805 capacitors

    What makes you think it is picoFarads? You can get up to 100uF in that size. Did you measure the ESR in circuit? If so, the reading is meaningless. Desoldering is most easily done with a hot air gun. Soldering is easier with a regular iron with a small tip. If you don't have tweezers, get...
  5. BobK

    DC Voltage conversion for miniature bulbs?

    Here is a circuit that implements my suggestion. V2 represents the voltage your instrument is sending to the old bulb. In my simulation, it varies from 2V to 3V. R3 represents your new 12V bulb. The chart shows how the voltage to that bulb varies from 8V to 12V when the input is 2V to 3V...
  6. BobK

    Circuit help

    No, it is not exactly what you were drawing. Can you really not see that in your circuit the output of the nightlight sensor and the gate of the MOSFET are connected to ground, and that in AudioGuru's corrected version they are not? Bob
  7. BobK

    Building Portable AC power supply

    The capacity of batteries are typically stated for a discharge over 20 hours. Higher discharge rates result in lower capacity, sometimes much lower. Bob
  8. BobK

    Replace Relay with TRIAC?

    Chris, Yes, "shit" is the mil-spec term. bob
  9. BobK

    Use of Splitters

    What do you mean by a splitter? All you need is to wire both to the power supply. But no, of course, a 1A unit will not power 2 1A devices. You need at least 2A and 3A would be better so as not to stress the power supply which probably came from China and is rated shall we say...
  10. BobK

    Partialy Discharging Capacitor

    The easy way is what I said, use a thyristor (SCR) to short the capacitor. This is not the most efficient solution since it still requires full recovery time on a shortened flash, but it is the simplest to implement. I believe this is the way older units worked back when I was into...
  11. BobK

    DC Voltage conversion for miniature bulbs?

    Been there many times! What brought you to Worcester? Oh, and the op amp does not need temperature compensation, it works on negative feedback and is inherently stable. But, on the other hand, If you think temperature drift would be a problem, then replacing the bulb with something it was not...
  12. BobK

    Replace Relay with TRIAC?

    More often called "noise." Bob
  13. BobK

    Partialy Discharging Capacitor

    230V would be correct if the current is linear in the voltage. But a xenon flash tube curve is not likely anything close to linear. Controlling the time of the flash is a much better option. An SCR across the capacitor can be fired anytime after the flash starts to quickly end it and dump the...
  14. BobK

    DC Voltage conversion for miniature bulbs?

    I gave you the complete solution. You do not need the part you are referring to. Bob
  15. BobK

    Building Portable AC power supply

    However. If whatever you are powering (this is certainly true of laptops and all low voltage devices) already is powered by a transformer that steps down and rectifies the voltage, you are better off to convert to that voltage directly with a DC-DC converter instead of first converting to 110AC...
  16. BobK

    Building Portable AC power supply

    To invert directly to 110V AC you would need 155V + some headroom, so maybe 170V DC. Inverting from that voltage will be more efficient than going up from 12VDC. You can make it a sine wave inverter by using a PWM signal that approximates the sine wave then filtering with inductors and...
  17. BobK

    DC Voltage conversion for miniature bulbs?

    Hmm. It seems like you might need a DC amplifier that can handle 3W of power. An opamp with gain of 4 plus a P-channel MOSFET output transistor might do it. The feedback for the amp would be from the junction of the transistor's drain and the bulb. Bob
  18. BobK

    Noob? Electronic car horn for bicycle

    Most likely you use the two + terminals for eight Ohms. Bob
  19. BobK

    9v Guitar Amp w/out LM386

    PD64, Perhaps you missed the word "not" in the sentence from the OP about using an LM386. Bob
  20. BobK

    Transistor

    Why? It is an inferior solution, which creates wasted energy and produces a lot of heat, while lowering the torque of the motor. The Arduino can output a PWM signal as well. Bob
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