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  1. kellys_eye

    Grid of tiny-linear-actuators

    Another idea. I've seen linear actuator assemblies (tiny stepper motor driving a helical shaft) that you commonly find in CDROM drives (head movement) that can be found for 'pennies' via the usual Chinese supplier route. If you assembled a load of them in a grid array and attached plastic...
  2. kellys_eye

    Grid of tiny-linear-actuators

    Wow! A 'bazillion' linear actuators :eek: Hope your budget is being paid by someone else! Can you even get such actuators with a diameter small enough to allow 1000 to be fitted in the space of a laptop?
  3. kellys_eye

    Uninterruptible power supply ratings: conflict between VA and W?

    Simply - most domestic electrical installations are billed based on a standard PF correction of around 0.9 to allow for losses in inductive loads in the users premises. The installed meter only measures 'real' power consumption and cannot correct for phase-loss. If your home uses a LOT of...
  4. kellys_eye

    Vo-Tech transformer lab station

    Pretty much useless imho - despite its retro/steampunk appearance. You'd get more use from 3 variacs (one per phase and infinitely adjustable) without having to 'select' the required tapping points - if you actually wanted to have a 'useful piece of test equipment'. Might be worth re-working...
  5. kellys_eye

    Grid of tiny-linear-actuators

    Suggest you use a standard 'pin board' and fit an actuator under it that can move in the X, Y and Z axes. Position the actuator X-Y then apply Z to push the pin(s) accordingly - rinse and repeat.
  6. kellys_eye

    Simple Low Frequency Sound Generator

    128Hz is readily derived from a standard crystal of 32.768kHz (i.e. a 'watch' crystal) using binary dividers. Then feed the resultant 128Hz to a simple audio amplifier - add a filter to 'smooth' the squarewave if you feel it needs it. Here's a simple oscillator/divider with a 2Hz output but you...
  7. kellys_eye

    Datalogging in computer

    How accurate do you need the recording to be? How often do you want to record it?
  8. kellys_eye

    Charging a smaller capacity SLA battery from a larger bank.

    Via a boost charge method. The battery requires around 14V to charge and a battery that is already charged (just off the charger) will only be around 13.8V, dropping quite quickly thereafter. Use a simple boost converter to power a lead-acid charging circuit.
  9. kellys_eye

    Charging a smaller capacity SLA battery from a larger bank.

    You normally use a split-charging diode arrangement - the solar feed goes to two diodes (suitably rated for amperage etc) and each diode cathode then connects to the individual battery banks. You also (but not always) have to compensate for the diode forward volt drop.
  10. kellys_eye

    Connecting and insulating wires in high temp environments

    Many ratchet crimp tools like the one shown have an adjuster to set the maximum crimping pressure and if it's set 'too tight' will cause core 'snipping'. Check the tool user instructions. Silicon sleeving is good for high temperature wiring or, as already suggested, woven fibre glass. If you...
  11. kellys_eye

    Hello, varactor(varicap) formula help

    You can only get this from either the manufacturers datasheet or by actual measurement of a specific device (applying control voltage and measuring the change over the permitted range of reverse voltage).
  12. kellys_eye

    Electrolytic capacitor identification

    The adjacent inductor points to an SMPS-derived supply onboard - quite common - and blown capacitors are a definite problem in some designs so your fault could just be pertinent to the design but the severity of the failure is quite surprising. If/when you change it I'd recommend powering up...
  13. kellys_eye

    Yorkville 100watt Mixer/Amp - Replaced Transistors

    The voltage sounds ok - ideally they are equal but to achieve that would require messing with the biasing resistors but the fault isn't being caused by such a small difference. Since the headphone jack is at the amp output it points to the SPEAKER being damaged - probably by the original fault...
  14. kellys_eye

    ECU unit

    Pics please. There are often devices bolted to the case (heatsink) that, if corrosion gets behind them, can allow the device to overheat/shutdown.
  15. kellys_eye

    Electrolytic capacitor identification

    Can you show where, on the unit, the capacitor came from?
  16. kellys_eye

    Inrush current smps.

    Is it a 'real' 18A SMPS or a 'Chinese' specc'd 18A SMPS?
  17. kellys_eye

    Forum Category Feedback

    I've got used to the changes very quickly and also find the way the sections are listed to be very easy to navigate. Nice move.
  18. kellys_eye

    'Deliberate' lifespan of modem/routers?

    I recently repaired my own router (Netgear) that had two duff capacitors in it. It had been running 24/7 for over 4 years! Planned obsolescence can be either ending support, changes in technology (improvements) or by cost-cutting measures resulting in lower quality components being used...
  19. kellys_eye

    Yorkville 100watt Mixer/Amp - Replaced Transistors

    Speaker negative leads or anywhere on the schematic that is labelled 'AG'.
  20. kellys_eye

    Electrolytic capacitor identification

    I'd be more concerned for WHY that capacitor blew up in the way it did......
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