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  1. crutschow

    want to use Headphones and main speaker

    Need to know exactly which are the jack pins on the other side of board.
  2. crutschow

    Decade counter to Momentary relay?

    Here's the sim using the output of a CD4017 to the relay driver:
  3. crutschow

    Audio signal conversion

    You could also use just a trimpot with the resistive element connected between the TDA7318 output and ground, and the wiper connected to the VU meter input. A 5k to 10kΩ trimpot should likely work.
  4. crutschow

    Decade counter to Momentary relay?

    Yes, that's certainly an option. The recovery time without the diode is about 3 R1C1 time-constants (to ≤0.25V at the MOSFET gate). With the diode it's slightly more than the fall-time of the input pulse.
  5. crutschow

    Decade counter to Momentary relay?

    You have D1 backwards. Simulation below of the modified circuit: I used an N-MOSFET to drive the relay, since the typical 5V relay coil draws too much current for the CD4017 to provide enough base current to properly saturate a BJT.
  6. crutschow

    Decade counter to Momentary relay?

    I don't see that as a real problem. A relay has a lot of hysteresis and, once it starts to open, it will not reclose to generate any "chatter".
  7. crutschow

    Decade counter to Momentary relay?

    Here is one approach: You select the capacitor size to get the momentary on-time you want. D1 is to allow rapid discharge of the capacitor for the next pulse. If you don't need fast recovery between pulses, then you could change D1 to a resistor (the resistor, of course, will reduce the on-time...
  8. crutschow

    want to use Headphones and main speaker

    All that would do is put the amp and headphones as a parallel load and I don't see how that would harm the amp.
  9. crutschow

    High Voltage Direct Current

    That's a blanket statement that's not true if the climate change is caused by the increase in atmospheric CO2, which seems likely, and the electricity to charge the batteries is generated by non-CO2 producing generating stations.
  10. crutschow

    High Voltage Direct Current

    Are you asking? Advantages: For a given peak voltage a 2-wire DC line can deliver about 80% of the power as an AC 3-phase line (√2 / √3) for the same current. If 3 wires are used for the DC line with two lines being opposite polarity and one common, then the DC lines would carry 160% of the...
  11. crutschow

    want to use Headphones and main speaker

    The only way I can think of to keep both on is to remove the cover and see if you can modify the headphone jack. Below is a typical connection for such a jack: The two stereo signals go to pins 2 and 3. When there is no headphone plugged in the signals go out pins 4 and 5 to the amp. When the...
  12. crutschow

    Decade counter to Momentary relay?

    Sorry but I can't really understand the circuit from your description. A schematic is the language of electronic circuits. Please post a complete one.
  13. crutschow

    Simple UA741 and 2N3392 circuit troubleshooting

    Don't see how it can work with no negative voltage source to the transistor emitter. How do you expect the emitter to go negative without that? Try adding a 1kΩ resistor from the emitter to -10V.
  14. crutschow

    Simplest BJT configuration for a SPDT, single pole double throw switch

    Need to know exactly what you are trying to switch as BJTs can only be used for that purpose for a specific set of conditions.
  15. crutschow

    Basic transistor switch

    Okay. But you just said there was a difference, you didn't say what the normal criteria is for a saturated transistor, so that's why I stated it.
  16. crutschow

    House vs apartment

    The worst thing I found about living in an apartment is noisy neighbors, where the sound (loud voices and/or music) comes through the walls, and also hearing people on the floor above walking around or doing exercising (ten minutes of jumping jacks can drive you crazy). It could be OK if the...
  17. crutschow

    Basic transistor switch

    As noted frequently on these sites, that's not good design practice when using the transistor as a switch. A forced beta of 10 is the usual value used.
  18. crutschow

    Receiver DENON AVR-4520CI without sound and heating the power outputs.

    Sorry, this is an English only site.
  19. crutschow

    Magnetic field and how it is dangerous

    What makes you think magnetic fields, of such low intensity are dangerous? Even the huge magnetic fields they use in MRI machines are only dangerous if you have anything magnetic in you clothes, which can cause mechanical injury from the forceful movement of the object into you body.
  20. crutschow

    Bias_T and inductor resistance

    Of course they do, as they generate a constant-current through the resistance being measured and measure the resulting voltage to determine the resistance. How do you think digital meters measure resistance? They don't work as well to measure a capacitor, since the meter reading update is...
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