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  1. kellys_eye

    Cannot get this circuit to work

    There's nothing wrong with the 741 or the 386 when used in this way. A 555 can't be used for a squelch application since it is a timer..... and the circuit shown IS a squelch. The 741 is simply configured as an AC amplifier followed by rectification and switching - switching the power to the...
  2. kellys_eye

    I need help, I want to monitoring a multi function meter over RS485

    The datasheet does say the RS485 is only applied on the MFM376-c version. Is yours the one with the suffix 'c'? It also shows the need to set the data stream parameters on the MFM device (baud rate etc) - have you done that?
  3. kellys_eye

    Safe storage of gadgets?

    The key would be humidity - which in and of itself will carry any corrosive salts to your equipment and deposit them appropriately. You could keep a dehumidifier running (preset for a minimum level?) but they don't run cheaply these days. Bagging the expensive stuff with silica-gel packs...
  4. kellys_eye

    I need help, I want to monitoring a multi function meter over RS485

    ..
  5. kellys_eye

    Cannot get this circuit to work

    FYI and others - I'm not the 'king' of anything....... ask my wife.....
  6. kellys_eye

    Cannot get this circuit to work

    Probably a result of some construction error..... show your layout etc.
  7. kellys_eye

    TFT touchscreen lcd display replacement info

    All over eBay (touch screen as well as LCD or both together) https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p3519243.m570.l1313&_nkw=AT050TN33+&_sacat=0
  8. kellys_eye

    TFT touchscreen lcd display replacement info

    Datasheet
  9. kellys_eye

    TFT touchscreen lcd display replacement info

    or Ali Express for under $30 https://www.aliexpress.com/item/32410264240.html?s=p
  10. kellys_eye

    TFT touchscreen lcd display replacement info

    Spare screens available via ebay: $99 https://www.ebay.com/itm/402532248152
  11. kellys_eye

    TFT touchscreen lcd display replacement info

    If we search using 'instrument' we get no where - it must have an actual purpose...... make, model number etc? Is there some reason you won't disclose this?
  12. kellys_eye

    Capacitor type in low pass filter

    Ceramic and mica are generally reserved for higher frequencies than the kHz range - you will be limited by the absolute minimum values required which will take you into the polyester, polypropylene, MLCC types. Check this out: https://www.elektormagazine.com/index.php/files/attachment/326
  13. kellys_eye

    How to drive a 12v 40w heating pad

    If the transformer can deliver AT LEAST the current required by the heating pads (being able to deliver MORE current is better as this puts less strain on the transformer) then there is no reason you can't use them.
  14. kellys_eye

    6A 250V US Plug security camera wiring problem

    Woah..>! No, no, no, no, no........!!!!! That pic (#2) is waaaay wrong. The cable should be secured under the strain relief and there should be NO VISIBLE copper wire left after the connection has been made to the socket pins. That bare wire is open invitation to another Big Bang Theory...
  15. kellys_eye

    Icom 260A memory back up battery issue

    Weird - I actually downloaded the schematic from that exact link..... I'll add it as the pdf I downloaded so anyone can reference it;
  16. kellys_eye

    6A 250V US Plug security camera wiring problem

    The power plug/socket on the camera is bog standard - I'd replace the whole power unit with a 'wall wart' with the appropriate 12V DC output and the correct plug.
  17. kellys_eye

    Icom 260A memory back up battery issue

    Measure the units standby current to determine what the consumption is when connected and in 'memory save' status. If the current level is 'acceptable' (determined by the actual current and the length of time you want to save the memory settings for - to get an idea of how large any battery...
  18. kellys_eye

    EAS 8.2 MHz antenna design help needed

    No. Told you already - look up antenna radiation patterns. You can't (easily) focus low frequencies and you'll NEVER do it at 8MHz. To do what you want you need to be using 900MHz and above (microwave frequencies) and, even then, it won't be easy. You're talking 'phased array' type antennas...
  19. kellys_eye

    EAS 8.2 MHz antenna design help needed

    (my bold in the quoted part) You can't. End of. The frequency is too low. Google yagi element calculator and research antenna radiation patterns to learn more.
  20. kellys_eye

    Repurposing a solenoid array to communicate with arduino

    The shift registers run at 5V (see the datasheet) so the board won't work unless you provide BOTH supplies to it.
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