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  1. Hero999

    help ...to control pulse width of a -15vdc pulse train

    I assume you're doing this the old way i.e. using logic rather than a microcontroller which might be easier. Stretching the pulse is pretty easy, you need a monostable which is falling edge triggered, a Schmitt trigger or similar will work. A CD40106 or 74C14 can be used, see the last page of...
  2. Hero999

    Two channel embedded audio module

    I don't know much about this but I can think of two options: get a stereo device or two devices and connect both outputs to the same amplifier.
  3. Hero999

    Replacement for 2SK533

    It's definitely N-channel. The current is specified as a positive figure (P-channel devices are often specified as negative) and of the PDFs I found using Google says so. The maximum IDS is 30mA, the characteristics are specified at 9mA.
  4. Hero999

    Designing DPLL with 555

    You mean the CD4007 circuit I posted? There's a note on the schematic indicating which pins to connect the power supply to.
  5. Hero999

    Solid state...transistor amp design problems

    Thread sorted, all double/triple posts are merged and the old posts restored. It's weird how theSILVERsound's post count is now when he has five; me deleting and undeleting all the posts has confused the forum software. The formula for the lower frequency cut-off is: C = 1/(2pi*FR) Where C is...
  6. Hero999

    Designing DPLL with 555

    If you have a spare CD 40xx NOT/NAND/OR gate you can can use it as an inverting amplifier with a gain of 1 which will save an IC.
  7. Hero999

    AUTOMATED PARKING SYSTEM

    I've never seen a system which completely automates the process. There are plenty of sensors though, normally sonar is used and one system I saw uses a camera mounted on the back of the car and a screen on the dashboard.
  8. Hero999

    Designing DPLL with 555

    If you don't have the 74Hc4046 the old CD4046 will work. If you're not allowed to use the proper IC then it makes life a bit harder for you. You could use an op-amp inverting amplifier to the input of the 555. Can you use the CD4007? You can make a VCO with it.
  9. Hero999

    Solid state...transistor amp design problems

    Start a quote with [quote] and finish with [/quote] I've corrected the quotes in your previous post. I'll look at the electronics and sort out the other posts tomorrow, I need sleep.
  10. Hero999

    Solid state...transistor amp design problems

    Thanks for trying but that's not what I meant you should do. What I mean is don't keep adding successive posts to a thread. If someone's replied since your last reply, use the reply button to respond. If no one has responded and you're just adding more information, use the modify button rather...
  11. Hero999

    What are Solder Pots used for

    I made a mistake in my previous post: there's no such thing as cored flux. What I meant to say is that you need rosin flux which is used in cored solder.
  12. Hero999

    How much does indoor and outdoor electronic billboard advertising in the Philipp

    Why do you keep making threads about billboards? Please keep all the questions relating to the same topic to one thread.
  13. Hero999

    Designing DPLL with 555

    I don't know why so many people continue to use obsolete components such as the 555 timer. The duty cycle also varies with the 555 so will not work with the phase comparator. If you're building a PLL then use the 74HC4046 PLL IC which includes a VCO and phase comparator...
  14. Hero999

    Solid state...transistor amp design problems

    Yes no amplifier will make any sound without a speaker and in this case a power amplifier is required to drive a speaker. I've merged your posts, in future use the modify button to add something to an existing post, it looks like this .
  15. Hero999

    Need help for motor driving with triacs

    TRIACs don't like switching capacitive loads. You probably also need a snubber network to protect the TRIAC from the back EMF.
  16. Hero999

    Solid state...transistor amp design problems

    And no one uses the old obsolete BC109 any more, go for the BC548 which is good for audio.
  17. Hero999

    Linear's ideal diode in a full wave bridge rectifier.

    You can't build a diode bridge from these because they don't have negative devices, only positive.
  18. Hero999

    12V DC to 120V AC converter... want to change it to 220V AC... can anybody help?

    This circuit doesn't work properly and it's pretty obvious all that needs changing is the transformer.
  19. Hero999

    "rocker motor, simple bracket and power supply" to animate our Hula Swirl Girl

    We can't help you because you haven't provided enough information. You first need to know the power requirements for the motor: voltage, current, AC/DC etc.
  20. Hero999

    high precise Temperature sensor

    You'll also need to use a much more accurate ADC which will require the software to be modified. I suggest you look at the schematic, read and understand the code. You probably need to start from scratch but some parts can probably be reused.
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