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  1. dorke

    Audio speakers

    How did you use the computer speakers ? They are usually powered units. Please explain. You can't get high power from the LM386 at best it is a 1W amp. Powering it with 6V you can get about 0.25W at 1% distortion. This will very quickly rise to 10%(awful quality) at 0.4W. You may be able to...
  2. dorke

    Transistor Help

    Well, Like Dave said above it is clear why it should not work. Here is the correct circuit. Don't forget to add the diode so that the Tr. will not blow !!!
  3. dorke

    ATTINY uC Sleep-Mode Functionality

    Yes it is possible. For lowest power consumption use the μC in power-down mode. Wake it up on interrupt from one of the sources: watch-dog timer or pin change. See chapter 7 in the datasheet About the battery life: Here is a nice and free calculator for that. Enter your parameters and find out.
  4. dorke

    Replacements for ACST6-7S and ACS108-6S

    Welcome to EP. These prats are still manufactured by ST and are available. Why do you need an equivalent? simply buy the originals!
  5. dorke

    RS422 to RS232 converter.

    Yes,de-coupling. It should be ceramic type, very short leads ,X or Y type(i.e X5R,X6R,X7R etc.) but not Z!
  6. dorke

    CO2 cannister valve

    Try to find something here. and here.
  7. dorke

    Reverse battery protection Diode

    Well, number 3 should be a bit above 0.5V,but basically it's o.k. Now,it is clear that if the power supply voltage is below(or equal) to 0.5 volts the diode is not conducting, it is Off and practically "reversed biased". Obviously if the power supply voltage is lowered further to 0V or below to...
  8. dorke

    Do you still need thermal paste when using a silicone elastomer?

    They are actually better.than using Mica isolators. It may help,but you need flat and clean surfaces and tighten the screws well. First thing to check is whether the Mosfets themselves are isolated in case there are "metallic back". If they are plastic ,they are obviously isolated. For...
  9. dorke

    Design of a DC voltmeter circuit

    @davenn, It looks like trying to make a "JFET VTVM" with an analog meter., most probably belongs to the Homework Help.
  10. dorke

    Reverse battery protection Diode

    I shell try to explain in the simplest way possible(In steps): Forget about the LDO for now,lets look at the resistor case only. For the diode to be conducting(forward biassed or ON), lets assume a minimum voltage of Von(about 0.5V) is needed. Thus the voltage at the Anode should be greater...
  11. dorke

    Hacking the buzzerbox

    @Mika, From the measurements you took at #8 It looks like there is always a DC voltage between 1 and 4 (8.5 to 12V). This means the schematic of the "buzz"(at the entry panel) showing a switch on the #4 pin line is just a "symbolic representation". It can probably be used to power...
  12. dorke

    Hacking the buzzerbox

    This diagram is almost identical to the one I made. Here is the slight mod. needed(pins 1-2 "swapped). Another note :The speaker is always connected between 2 and 4.
  13. dorke

    Hacking the buzzerbox

    The schematics I posted at #4 is what I made of @Mika 's actual board(from the photos). There is nothing there but 3 simplest N.O. push-buttons. That can be checked, a photo of the other side to verify should be enough(no other components). I wouldn't disconnect it.
  14. dorke

    Reverse battery protection Diode

    Let;s try it step by step. Can you explain,to yourself and to us, the forward/reverse of the diode in the circuit below? show us. @AnalogKid ,chewing the food for the OP doesn't really help him,it takes self work and understanding ;) .
  15. dorke

    Comparison of 1$ microcontrollers

    Dear Harald, This looks like a great link. This type of comparison is very time consuming ,some μC are most probably not very familiar to most . I think it should belong to the "Resources" section for the benefit of many. Please add this there.:)
  16. dorke

    Reverse battery protection Diode

    Try to replace the LDO (diode cathode to GND) with a resistor. Can you now understand ?
  17. dorke

    Reverse battery protection Diode

    What do you think happens? Try to answer yourself,with and without the diode.
  18. dorke

    Reverse battery protection Diode

    An LDO is a 3 terminal creature,you left out the GND terminal,added in blue. Green -forward bias. Red -reverse bias. Kapish?
  19. dorke

    Getting Started - Help

    If you are studying EE in collage you will be a pro (after you sweat a bit;)) The best books for learning the theory are the text books you have,or may have. Some Text books on the basics (very old and good,I used them at my time): "Basic Circuit Theory" by Desoer and Kuh. Scaum's "Theory and...
  20. dorke

    Getting Started - Help

    Welcome to EP. For answering your questions you should tell us what is your goal and background education. Do you want to be a pro?a hobbyist? build things? in what area etc. The field of electronics is vast and now days specialization in narrow ares is very common. Although some of the older...
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