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  1. gorgon

    LEDs in series to 240V?

    The dimmer could be ok, but if it is just clipping the sinus curve, so measuring it with a AC voltmeter can fool your calculation, since it is made to show a RMS value. If you want to see the true peak value you should use an oscilloscope an verify the value. A capacitor will never 'clip'...
  2. gorgon

    Is this reasonable power dissipation when driving transistor base?

    If you measure 10V over 1k(R1) you are sourcing 10mA into the base of Q1, more than enough to saturate Q1 to supply 360 mA you'll need for your 12 LED panels, each drawing 30mA.(you'll drop a small voltage over the transistor) I think you mix base current with collector current in your...
  3. gorgon

    LEDs in series to 240V?

    The main problem here is that you will not get 240V DC out of this, but more like 340V peak with ripples down to whatever the capacitor manage to supply between the peaks. The second problem is that LEDs does not behave like resistors, they don't increase the forward voltage very much when the...
  4. gorgon

    Audio Switching?

    You don't tell if the relay should switch OFF when the signal disappear, or stay on? TOK ;)
  5. gorgon

    Hex Inverter Outputs Low

    Just to check, have you supplied both 7404 chips with 5V and 0V? Current limiting resistors in series with the LEDs? TOK ;)
  6. gorgon

    Personal Attack Alarm Circuit Diagram

    Use a standard 2.5 - 3.5 mm audio jack as the pin should be the simplest. TOK ;)
  7. gorgon

    What is this component?

    Together with the MOVs I would think it is a gas overvoltage arrester. TOK ;)
  8. gorgon

    M.U.N.T.E.R. (Z80-based computer)

    OK, munter is 'merry' in norwegian, and I suppose it also could be a merry chase getting things to work? :D Z80 is a great MCU, I did many projects with it in the late -80s. I just wondered about your serial interface, I suppose it is for a tape interface? Why not use a flash chip instead...
  9. gorgon

    Animatronic Tail

    How good is the UP printer? Do you need to sand the parts much to improve the surface? I'm looking to buy a 3D printer in the future and if you can give me some hands on experience report it would be nice. The tail looks great, but in my experience you need some big servos to drive this type...
  10. gorgon

    M.U.N.T.E.R. (Z80-based computer)

    I'm wondering about the heading for this project, what's M.U.N.T.E.R. indicating? Please excuse my lack of language references. Has this abbreviation something to do with the arcane serial interface? TOK ;)
  11. gorgon

    Power supply prj with LM2576HV

    If you take a look at the datasheet you'll find some recommendations. As a general rule, 3A current will need a relative big magnetic core. Datasheet: http://www.ti.com/lit/ds/symlink/lm2576hv.pdf check page 15, fig 9. Here are links for the recommended parts...
  12. gorgon

    Assignment help (basic queuing system)

    Nothing is visible beside the red 'X'. TOK ;)
  13. gorgon

    voltage for IC ?

    5V supply and clock is good for this part. A general rule is never to have a higher voltage on the input signals than the supply voltage you use. For this particular chip you can use a supply of up to 15V. For a 5V signal, 5V supply is good. TOK ;)
  14. gorgon

    adjusting the LM317LZ IC

    Depends on the package. If you use a TO220, you have the flat side down on the table, the screw hole up, and the pins down towards you. The correct pinout from the left to the rigth is: ADJ, VOUT, VIN. Should be rather simple if you take a look at a datasheet. TOK ;)
  15. gorgon

    4017s lighting up 60 LEDs sequentially

    I found this http://www.nxp.com/documents/data_sheet/HEF4894B.pdf. It's a 12bit shift register with buffered outputs. This you only need 5 of to drive the 60 leds. TOK ;)
  16. gorgon

    Help asap

    Sometimes you use pullup on signals controlled by tri-state outputs, to establish a default state, or in a wired-and/ -or situation to save gates. If the resistor is too low you'll have problems driving it. Fan out and in is a little discussed theme today, with CMOS all over the place, but still...
  17. gorgon

    4017s lighting up 60 LEDs sequentially

    You could also use a >=6bit binary counter, a number of 3bit to 8 decoders driving the leds. You'll also need a couple of gates to reset the counter at 60, back to 0. You'll need 9 74hc138 decoders, 8 to drive the 60 leds and the last to select one of the others at the time. TOK ;)
  18. gorgon

    Help asap

    If you use a standard 4xxx series cmos chip at 9V, pullup, and pulldown resistors should be a bit higher than 1k. 22k should do nicely, this will load any output connected with 0.4mA. If you use 1k you'll 'over'load each output with 9mA, way to much. For external signals that can supply 10mA...
  19. gorgon

    Problems with using a 4049 Inverting Hex Buffer

    No it does not look correct! Just for a starter, where is the signal high, input(pin3)? You should add a series resistor between the output (pin2) and the base of the transistor (Q) If you use 2k2 in series and 10k to pull down the base(R) you should be good. As it is now, the output...
  20. gorgon

    For the young, aspiring Engineers!

    Or green leakage cable. Maybe some spade oil? TOK ;)
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