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  1. Alec_t

    A Stretch

    If that circuit gives just hum and no guitar sound, I suspect the fault lies with something simple, like a missing ground connection. Do you have battery negative, guitar plug ground and pre-amplifier input ground all connected together?
  2. Alec_t

    Is there any risk of shock from attaching or detaching wires to a 9V battery?

    So your zapper is fed with AC voltage which probably gets rectified to drive an oscillator. The oscillation gets stepped up by the transformer then rectified and stored on the 2000V cap. If there is a bleed resistor across that cap, it's not evident from the pic. Methinks the cap would hold a...
  3. Alec_t

    Is there any risk of shock from attaching or detaching wires to a 9V battery?

    Both. The flash duration in a camera flash unit (other than a disposable camera) is usually adjustable by the microcontroller in the camera or standalone flash.
  4. Alec_t

    Easy Wiring Question

    Those are strange symbols for switches, but it looks as though pressing the bell switch shorts the hot to neutral or ground (either of which should trip a breaker) and pressing the light switch energises both the bell and the light. You shouldn't be using the ground wire to carry load current.
  5. Alec_t

    Is there any risk of shock from attaching or detaching wires to a 9V battery?

    Depends how the circuit has been designed. Only if you have a meter rated to handle the very high voltage.
  6. Alec_t

    Can someone simulate this diagram for me please

    Yes. The 10k affects the output voltage, but I don't know what you mean by 'a certain voltage'.
  7. Alec_t

    Is there any risk of shock from attaching or detaching wires to a 9V battery?

    You switch off the device and make sure that any capacitor in the device has time to discharge. This may take a second or so if the circuit has been designed properly to include a discharge path, or may take a lot longer in a cheapo circuit with no such intended path.
  8. Alec_t

    Can someone simulate this diagram for me please

    NSCW100 (one of the LEDs in the default LTS installation).
  9. Alec_t

    Can someone simulate this diagram for me please

    Apart from an initial 0.5mS or so duration start-up current peak of ~700mA while the 22uF cap charges, the top LED passes only a few mA required mainly by the 555. Here's my simulation output. The voltage is dependent somewhat on the forward voltage drop of the particular LEDs used. Note: My...
  10. Alec_t

    Is there any risk of shock from attaching or detaching wires to a 9V battery?

    A bug zapper includes an inductor for stepping the voltage from the battery up to a very high voltage which may well be rectified and held on a capacitor. That could be enough to give you a nasty schock. The same arrangement is used in a camera's electronic flash. The camera manual would...
  11. Alec_t

    Is there any risk of shock from attaching or detaching wires to a 9V battery?

    No, unless the battery is connected to a large inductive load. That will generate a high back-emf when its current is interrupted; high enough to give a nasty jolt but unlikely enough to kill you (unless you have a pacemaker or heart-condition).
  12. Alec_t

    Woo-Woo What electronics do these invisible earphones have in them?

    I'd be very concerned by this statement in the ad's product description :- "NOTE: It must touch your ear drum to function. If not, the sound will be too quiet." Our health services are already stretched during the pandemic, without having to cope with cases of ear drum damage when idiots get...
  13. Alec_t

    A Stretch

    Connect the +ve side of the cap to the opamp input.
  14. Alec_t

    A Stretch

    That's what the schematic shows. I'm surprised a 470nF is polarised, however. Using 470nF instead of the 1uF shown will reduce the bass response a bit.
  15. Alec_t

    A Stretch

    Possible on veroboard, but fiddly, by bridging tracks (as per post #13). Another mounting option is to bend a tinned copper connecting wire into a hairpin shape, grip the component in the bend for soldering, then solder the legs of the hairpin to the pcb and cut the bend off.
  16. Alec_t

    Error uploading photos here

    It is helpful to reduce image sizes where practical, to assist site-visitors who have poor or expensive Internet services.
  17. Alec_t

    Faulty treadmill control board

    Are any electrolytic capacitors bulging/leaking?
  18. Alec_t

    Cost efficient pipe inspection solution

    How deep is the pipework buried? Is the 5k stretch reasonably straight with no obstructions? Are there any hazardous residues in the pipe? Can the pipework be totally emptied before an inspection? Can it be pressurised to conduct an inspection?
  19. Alec_t

    How to redraw if a drawing have legal limitations ?

    As said, seek legal advice. The actual wording could be important. For example, the restriction might (albeit unlikely) apply only to the original drawings and not to any version of your own creation. Copyright law can be tricky and does vary between jurisdictions.
  20. Alec_t

    Dither for PWM circuit

    Welcome to EP, ccebeci, but did you notice this thread is over 2 years old?
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