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  1. Alec_t

    Any ideas - Rotary momentary switch?

    Nice one!
  2. Alec_t

    Vintage doorbell issues

    Has something gone missing? That cup-like thing to the left of the resistors looks like the end cap of a fuse.
  3. Alec_t

    Easy Machine To Wind Transformer

    One like this.
  4. Alec_t

    Russian electronics help needed.

    :confused: Wouldn't that be100k, not 10k?
  5. Alec_t

    Easy Machine To Wind Transformer

    That's cheating! My hand-drill was hand powered :p.
  6. Alec_t

    Easy Machine To Wind Transformer

    Welcome to EP! Unless you are going to make lots of transformers a motor-driven winder is unnecessary. I've successfully wound coils simply by mounting the coil bobbin in the chuck of a hand-drill clamped in a vice, the supply spool of wire being allowed to unwind freely and a slight tension...
  7. Alec_t

    help connecting 555 timer

    Then to be certain of correctly identifying the right sensor would require a timing precision better than 1%. Methinks a chain of 555s won't do it. This project cries out for an MCU scanning a matrix.
  8. Alec_t

    Half bridge inverter

    That's better! How much dead time do you have between the high and low-side drive pulses?
  9. Alec_t

    Half bridge inverter

    How/where are you connecting the motor? A 1 phase induction motor needs alternating current. Your 1/2 bridge circuit provides only chopped DC ! DC can fry an induction motor.
  10. Alec_t

    Automatic Re-setting target

    Roughly what is the weight of the target and how quickly must it be reset?
  11. Alec_t

    High temperature controller circuit

    Googling 'thermostat circuit' brings up lots of hits. Presumably you will be using an MCU for the comparator/setting functions in the signal conditioning stage? The SSR should be the last link in the chain, unless the heating devices and switching operations you specify generate EMI which needs...
  12. Alec_t

    High temperature controller circuit

    Welcome to EP! Perhaps something like this would be a starting point. Further signal conditioning would be needed, for driving an SSR or similar.
  13. Alec_t

    Semi Automatic water overflow controller

    Did you also add the pull-up on Q2 base?
  14. Alec_t

    TLC555CP timer help

    Not unless you have some timing components attached correctly too ;). You should then see a reasonably square wave, unless you are working at a very high frequency or have a heavy resistive or reactive load on pin 3.
  15. Alec_t

    Where to find Single Phase Brushless DC Motor, or way of conversion

    So how do you propose to reverse it? Simply reversing the supply voltage (i.e. by using an H-bridge) won't do it.
  16. Alec_t

    weatherproof, low-current mini LEDs on long leads?

    I think twisted pairs of ordinary fine gauge enamelled copper wire would suffice, provided it isn't subject to chafing on branches. I'd use an SMD LED soldered to a wire pair and waterproofed in a blob of clear epoxy or silicone (not hot-melt glue, as that goes opaque under UV exposure). Another...
  17. Alec_t

    Any ideas - Rotary momentary switch?

    How about one of these (albeit a tilt/push action rather than rotary)?
  18. Alec_t

    LM13700 voltage controlled LP filter derivation

    I was considering voltage change; not absolute voltage. dv(out) = dv(in).
  19. Alec_t

    Can you detect leaking batteries electronically?

    I bet your smoke alarm (you do have at least one, don't you? :eek:) or other hazard alarm does that.
  20. Alec_t

    LM13700 voltage controlled LP filter derivation

    The voltage on the emitter of the Darlington is always 2 diode drops below the base voltage. Therefore any input voltage change at the base is matched by the same output voltage change at the emitter. Hence the gain is 1.
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