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  1. Externet

    Any 433/315MHz receiver hacker around ?

    Hi. Those cheap general purpose modules meant to receive 433MHz signals... how to make them work at ~140 MHz, or 150 MHz, or 100 to 200 MHz ? I assume other inductors/capacitors should work shifting tuning, if the chip is capable... Know any links to someone doing it ? How would you do it ...
  2. Externet

    Have a little fun...

    ---->
  3. Externet

    Do I understand what this does ?

    Hi. Hitting the 'trigger' momentary switch, the load is energized. Hitting it again, load de-energizes. From 2 to 4 Amperes load, from 3 to 6 V supply. ---->...
  4. Externet

    What is the series-parallel configuration ?

    Hello all. Three backlight strips from inside an Emerson-Funai TV model LF501EM5F (50") Wired by three pairs of connections to its supply board. How to find out the supply; or the series parallel configuration of the emitters ?) Strips are 23 emitters each, but cannot see its...
  5. Externet

    Wanted: Wanted: Ramsey AR2 receiver, kit or assembled.

    Hi. If you have one of those receivers behind the spider webs, let me know
  6. Externet

    Not-reversible fan motor ?

    Hi These common fans spin direction is not reversible, or are they ? Yes, they can be flipped. But when permanently mounted in a ceiling duct, it is too much to ask. What is the proper name for these type of motors ?
  7. Externet

    Selfie poles...

    Never used one, know nothing about. How is the camera triggered from the pole handle to take a picture ?
  8. Externet

    Suggest hard to find switch component, please ?

    Hi. Does anyone know a vendor source for a sliding magnet captive in a slot component for a trough-wall activation of a hall effect sensor or reed; that can be glued/attached ? The one in first picture is molded into the body; am looking for something that can be attached to an existing wall as...
  9. Externet

    Types of LED bulbs inside circuitry ?

    Hi. Some plain 120VAC LED bulbs do light up faintly as intended when connected this way, some do not. What could be different inside the bulbs, is there different circuitry 'architectures' in the industry ...
  10. Externet

    Frequency response ?

    Hi. For plain indicator LEDs, nothing fancy, rarely published in specs... What could be the typical maximum frequency response ? Do they go beyond 10MHz ? Varies with color/chemistry ?
  11. Externet

    Receiving a radio signal...

    Hi. When a radio receiver is tuned to say, 100 MHz; its local oscillator is at say 110.7MHz, the mixer stage produces a 10.7MHz intermediate frequency for later demodulation. If the broadcast ceases to emit, goes off the air; Or, shifting tuning to a blank unoccupied frequency; Or, shorting...
  12. Externet

    Anyone has schematic of ANY printer with USB port ?

    Hi. If you have a schematic of ANY printer with USB port; can you please check if 5V is provided at its jack ?
  13. Externet

    Magnet pole pieces...

    Not exactly electronics; please delete if improper. A magnet exhibits its field as demonstrated with iron filings aligned between its poles. Say you have an ordinary bar magnet 1cm x 1cm square, 10cm long Such magnet (N,S at left) fitted with long, straight, parallel pole pieces (upper ====...
  14. Externet

    Any expert in radio-controlling drones ?

    Hi. Is there 2.4GHz drone receivers that work on 3V supply ? What about less than that, like 2.5V ? Looking for a mile range; what transmitter power is reliable on line-of sight ? 0.5W ? 0.2W ?
  15. Externet

    Markings on analog moving coil meters...

    Hi. V. A, VU meters usually have markings on the bottom of the scale. I suppose tell full scale current, internal resistance... Were to look for the meaning ? Is there a standard for markings ? Several types:
  16. Externet

    Green 532nm DPSS laser pointer...

    Hi. Looking to make a 5mW(optical) at 532nm generic cheap laser pointer module that operates on 3V (2xAAA cells) work from 4.2V fully charged to 2.5V full discharged 18650 cell. The Vf for 808nm is supposed to be 1.9V. Such pointer is supposed to have a current regulator IC built in. Would it...
  17. Externet

    Once a minute chirp...

    Hi. Trying to make an about once-a-minute chirp/beep/chime, capacitive? resistive? coupling from 120VAC. Capacitor, rectification, slowly rising DC trough a very large resistance until the rising level discharges a short (0.5 second?) burst to a piezo buzzer emitter kind of circuit. Then, start...
  18. Externet

    Obbey the president...

    Spectacular ---->
  19. Externet

    Direct connecting solar panel to 18650 lithium cell...

    Hi. If a 1 Watt little solar panel outputs 4.0V at full sunlight; direct feeding a lithium cell will charge it to that maximum 4.0V at a maximum capable rate of 0.25A into a discharged cell, reaching perhaps ~85% state of charge. If the solar panel is 4.5V instead; it will apply overvoltage to...
  20. Externet

    Hight input impedance DC buffer ?

    Hi. I believe am loading my circuit too much and collapses. Am I seeing it wrong ? A 7555 IC as astable has 100KΩ as 10μF capacitor charge path and 100KΩ at its discharge path for ~ 0.2 Hz I want to use the oscillation at the capacitor, that goes from ~1VDC to ~2VDC (1/3 to 2/3Vcc) triangle...
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