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  1. crutschow

    Searching for a term

    Overvoltage circuits typically do that (often with an SCR) to protect a load from excess voltage.
  2. crutschow

    why 74hc inputs are high by default?

    Normal operation is to have the input driven high or low by an external signal, no pull-down resistors or inverters needed, so I don't understand your question. What's your definition of "normal"? If the input is not being used, than just tie it directly to ground or V+. The LTspice models...
  3. crutschow

    Faraday Cube

    As stated, you need some type of external antenna to listen to FM. How far away are the stations you want to listen to? Do you get good reception if you move the radio outside? What sort of antenna does the radio have now? Since you apparently have the internet, you might consider an internet...
  4. crutschow

    BJT Cascode Amplifier

    Start with the desired collector current and work from the bottom up. Think about how the circuit works. Hint: The collector current of Q1 is determined by Q1's emitter voltage across Re, and Q1's emitter voltage is determined by Q1's base voltage. Do you know what the typical Vbe of a BJT is...
  5. crutschow

    Modified sinewave to pretty good sinewave?

    Also can you provide the measured voltage at each step of the quasi-sinewave? I did some simulations for a 4-step quasi-sinewave with equal 1/3 voltage steps, and with 1/2 time at the peak and 1/4 time at each step (below). For the same RMS voltage value, the peak voltage of the quasi (green...
  6. crutschow

    Modified sinewave to pretty good sinewave?

    I have absolutely no idea what you are rambling on about. Makes no sense. Standard AC mains power is a sinewave.
  7. crutschow

    Modified sinewave to pretty good sinewave?

    Can you approximate some times for the various step levels?
  8. crutschow

    Modified sinewave to pretty good sinewave?

    Microwaves normally aren't operated for more than a few minutes at a time, so that may be okay. Measuring the microwave current/power with both the mains sinewave and the inverter will tell you if it is drawing excess current with the inverter waveform. A power measuring device, such as the...
  9. crutschow

    A stable vibrator circuit 12 volt dc supply

    How much current do the LEDs draw?
  10. crutschow

    Capacitance rules...

    Unfortunately, for whatever reason (bad day at home?), there are a few on these forums who sometimes act like they are still in high school, and demean and bully neophytes. Perhaps they think they are funny. Just ignore them.
  11. crutschow

    Capacitance rules...

    Especially since the stored energy is proportional to the square of the applied capacitor voltage.
  12. crutschow

    Capacitance rules...

    That is correct. Again no, that is not what I said. Do not confuse the capacitance value with the charge stored on a capacitor, which are two related but independent values. as you initially stated. The term "rated 20uF of storage" is not a proper statement. It's 20uF of capacitance, but the...
  13. crutschow

    Capacitance rules...

    The capacitance of a capacitor is the amount of charge it stores per unit of voltage. The capacitance does not change with voltage but the amount of stored charge does. You do not see to have a proper understanding of what a capacitor does. That's basically true.
  14. crutschow

    Capacitance rules...

    It should be rather obvious that if you put capacitors in parallel, the capacitance would double, and the voltage rating stays the same, since they both experience the full voltage. If two identical capacitors are in series, then the applied voltage is divided between the two, with the voltage...
  15. crutschow

    Original way to use car radio as a garage radio

    I thought, perhaps he was thinking of powering the radio from the charger without a battery. But I see now he just mentioned that as a way to charge the batteries.
  16. crutschow

    Subwoofer repair

    What is the music signal source for the speakers?
  17. crutschow

    Original way to use car radio as a garage radio

    I was concerned that the output voltage on the battery charger without a battery load would go above the 14.5V or so maximum voltage of an alternator connected to a battery.
  18. crutschow

    Original way to use car radio as a garage radio

    Yes, but chargers don't but out a steady DC, they use the battery for that. So you'd have to connect it to a 12V battery to get smooth DC. Also the charger by itself will likely output a much higher voltage than 12V.
  19. crutschow

    Original way to use car radio as a garage radio

    That should work fine, no dream, but you don't need 4 gauge wire, as that's for carrying starter level current. For the radio you shouldn't need anything larger than 16 gauge. But put a 10A fuse in series with the battery wire to protect against accidental shorts.
  20. crutschow

    Subwoofer repair

    Scratch my previous post, Apparently those monitor speakers are self-powered. But is does look like Blue Sky is still in business. Is that not true?
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