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  1. chopnhack

    Differences between LTSpice and Real circuit and why?

    Bingo, Bravo Adam!!! No, I used a generic LED and now that you mention it, I was curious as to why when I selected different LED's from spice I ended up having different current values across the LED. I can only guess that this is because of an internal resistance inside the LED? If I wanted...
  2. chopnhack

    Differences between LTSpice and Real circuit and why?

    Maybe someone can attempt to help on this question. As you can see below in the waveform, the circuit works as expected. I added C3 to smooth out the transitions between the oscillations. The value was derived by watching the output until it was clean. D3 is an LED that in real life shows only...
  3. chopnhack

    More efficient LDR "dark" switch?

    Done, but unfortunately still nothing.
  4. chopnhack

    More efficient LDR "dark" switch?

    I only have a 0.5M pot, but adjusted to max, the circuit still does not light.
  5. chopnhack

    More efficient LDR "dark" switch?

    I misread Harald's initial advice, I thought he was stating that I could simply increase my resistance in both halves of the divider thereby lowering how much current would pass through to the rest of the circuit. I thought that this was good advice and would save some energy, but in practice I...
  6. chopnhack

    More efficient LDR "dark" switch?

    I love it, but in this case I am trying to stay strictly analog. My programming skills and deciphering of the PIC registers is not quite there yet. If I must stay at 0.125mA on standby, I guess I can live with it, I was just trying to eek out a little more efficiency and thought transistor as...
  7. chopnhack

    More efficient LDR "dark" switch?

    With LDR out of circuit, there is a noticeable difference in brightness with collector of first to 3v as compared to collector not connected. 2mA vs 0.5mA
  8. chopnhack

    More efficient LDR "dark" switch?

    Yes, the LED's do come on. Do you mean to remove the connection to the second transistor's collector first?
  9. chopnhack

    More efficient LDR "dark" switch?

    Unfortunately, I tried this circuit with two 2n2222, (closest thing I have on hand to the bc547) without any success. I measured to see if there was any current at the second transistor base and there was none. Is it possible that there is simply not enough current being passed to the first...
  10. chopnhack

    More efficient LDR "dark" switch?

    Good solution, just increase the overall resistance of the voltage divider on both sides (no net effect on the triggering properties). So I could increase the resistance of the 22k resistor and add the same amount to the LDR. I will give that a go, thanks! @Harald Kapp - Well I gave it a go...
  11. chopnhack

    More efficient LDR "dark" switch?

    The circuit that is switched should consume no more than ~20mA (and quite possibly as low as 10mA).
  12. chopnhack

    More efficient LDR "dark" switch?

    Can anyone assist me with making a LDR switch? I specifically need a high efficiency and inexpensive setup since the intended circuit will run off of one 2032 battery. The switched circuit will consist of two small led's and a very low draw IC. The switch as pictured below gets switched on when...
  13. chopnhack

    Decoupling a cmos based 555?

    @BobK Thanks! That is a great explanation, I was thinking of the cap as a mini battery - keeping the supply rail steady and thus being battery fed, in my design, would be unecessary. Thanks again for the clarity in your answer and a good catch. Just a note: from some datasheets, it says that...
  14. chopnhack

    Decoupling a cmos based 555?

    I don't think it requires it since it is fed by a stable battery - this of course may depend on the current drawn for the circuit. I am basing this on less than 20mA draw from a c2032 3v lithium battery.
  15. chopnhack

    Decoupling a cmos based 555?

    Do you think that a 7555 requires decoupling the input voltage if it is battery fed? Please leave your reasoning in the reply, thanks!
  16. chopnhack

    8-Pin Development Board

    Hi Hop, thanks for the detailed reply. I am sorry to say that it escapes me a bit. I looked over the relevant sections that you pointed out, page 45 of the pic12f675 datasheet as well as the referenced section in the IDE users manual and I am just not getting it. I can share with you what I have...
  17. chopnhack

    8-Pin Development Board

    I am not sure Hop. I looked at the data sheet on the confi. bits but didnt see any information about disabling what you mentioned.
  18. chopnhack

    8-Pin Development Board

    Thanks Hop! I know the PIC's can be difficult to get running, I think its worthwhile though, there is so much that can be done with them! I am using a 12F675. JP2 is by one of the board mounting screw, its a black header (silkscreen labelled as ICSP)
  19. chopnhack

    8-Pin Development Board

    Doing some more reading on PIC programming I came across a schematic that made me question whether or not this pot will function as expected. One leg of the pot(red arrow) needs to be connected to 5v potential for the pic (pin 3) to see the changes in voltage on the analog channel. Also the...
  20. chopnhack

    8-Pin Development Board

    Thanks Constantine. The silkscreen terminology is loosely used, but in electronics it refers to the component outlines (as you mentioned) in graphic software layouts. Traditional silkscreen is a method still used today for t-shirts and what not.
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