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  1. Alec_t

    So, how many "watts" is a 9-volt battery?

    For 5 hours read 9 hours.
  2. Alec_t

    1V audio burst every OTHER pushbutton

    Rather than use two photo-transistors and a moving LED, which would eventually lead to fractured wiring, have you considered using two static photo-interrupters and a moving light-blocker?
  3. Alec_t

    Car Battery Powered House Ideas, Questions

    ... and lack of fresh food, and going stir-crazy, and ...
  4. Alec_t

    Mic detection circuit

    Let's hope so!
  5. Alec_t

    Can I use a blender motor as a fan?

    He probably will be if he doesn't get the revs down! ;).
  6. Alec_t

    Help with a flasher circuit with 555 Timer IC

    That's OK, Chris. Happy for someone to pick the ball up if I drop it :). Thanks for the welcome.
  7. Alec_t

    Change LM2575 minimum input voltage to 8 volt

    That range is certainly mentioned. The point is (so far as I understand it) that the OP doesn't want to over-discharge his battery, so he'd really like the IC to shut off completely when the input drops to 8V.
  8. Alec_t

    Mic detection circuit

    Well the solution depends critically on what the action of the mic switch is, i.e. does it short the amp input to ground or not.
  9. Alec_t

    Help with a flasher circuit with 555 Timer IC

    The 6V source was chosen for proof of concept because we don't know the LED type or spec, and the 3.7V source in post # 1 doesn't leave much headroom for current control if white LEDs are required. Agreed, if we're talking red bike lights (the OP hasn't specified use or LED colour/spec) and...
  10. Alec_t

    Charging AGM batteries

    Is 120V the input voltage or the output voltage? If output, then that is too high for a charging voltage. If input, then a 24V output is not enough. You have not stated the Wattage of your inverter?
  11. Alec_t

    Mic detection circuit

    Is that 'nothing' as in infinite resistance (open circuit), or 'nothing' as in zero Ohms (short circuit)?
  12. Alec_t

    Help with a flasher circuit with 555 Timer IC

    D8 provides a voltage drop so that the LED brightness will be the same whether the LEDs are turned on via the manual switches or the 555's discharge transistor on pin 7.
  13. Alec_t

    Microwave Door Switch

    The main power transformer.
  14. Alec_t

    Mic detection circuit

    According to the datasheet :- Impedance: 600 Ohms ± 30 % Does the switch a) disconnect the mic internally from the cord, b) short the mic or c) control power to an in-built pre-amp?
  15. Alec_t

    Change LM2575 minimum input voltage to 8 volt

    Which version of the LM2575 do you have? The TI datasheet for the LM2575-5.0 gives specs for supply voltages in the range 8V-40V, but that doesn't mean the chip will suddenly stop drawing current when the input voltage drops below 8V (or 7V). Even in the 'Off' state the chip draws ~200uA. You...
  16. Alec_t

    Help with a flasher circuit with 555 Timer IC

    I'll revise the suggested circuit if you can identify the issues, Chris. (My interpretation of the OP's intentions may be wrong.)
  17. Alec_t

    Help with a flasher circuit with 555 Timer IC

    Is this the sort of thing you want? I've included a push-switch to prevent the battery being drained by the 555's standby current.
  18. Alec_t

    Car Power Inverter

    Another hazard a car stereo system has to face is extremes of temperature. I doubt a domestic stereo would fare well.
  19. Alec_t

    Microwave Door Switch

    I wouldn't risk it. The microwave is a largely inductive load.
  20. Alec_t

    Heat pad project

    It boosts voltage (but requires a corresponding supply current increase). It's cheaper and easier to buy one than build one.
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