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  1. D

    Working around garbled LCD display on a blood-pressure monitor

    Usually the display cable is compression attached via zebra strip. You can clean that interface, if it exists, I have recovered several dirtbag consumer items that way. Regards, Dana.
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    USB Voltage sensors on windows

    Wireless sensor Network : https://techtutorialsx.com/2021/11/02/esp32-dynamic-sensor-network/ Google "esp32 sensor network" Regard, Dana.
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    Subwoofer repair

    1) Any signs of heat, post a pic of bottom side of board. 2) Any bulging or leaky caps ? 3) Any burnt resistors ? Google "poor solder joints" and look at images found so you can inspect bottom of board for cracked joints and high current melting...... Regards, Dana.
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    Reading data from AT21CS01 using an Arduino board

    You need to post your code. What Arduino board are you using. How are you wiring uop the EEPROM to the board, a schematic...... Help the forum help you with basic info.... Regards, Dana.
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    Help identifying resistor

    To determine if the R is ok requires doing a Kelvin connection measurement. An excellent reference handbook for these types of measurements : https://www.tek.com/en/documents/product-article/keithley-low-level-measurements-handbook---7th-edition...
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    I need help with a project !!

    The MQ7 has an internal heater to warm it up, and at 5V and its 33 ohm R the current is pretty high at 150 mA. Many of the Arduino boards do not have that high a current regulator. https://www.sparkfun.com/datasheets/Sensors/Biometric/MQ-7.pdf Regards, Dana.
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    I have no idea, please help. Identifying a component and how to fix.

    Do a 3D print design or is part you are talking about part of the electrical contact in the switch ? Obviously you have shaken the radio, given it a little whack on a bench, to shake loose the part if its hung up in a wire/case inside radio.....? If its magnetic swept the carpet or floor with...
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    Wifi woes

    Go to YouTube and search on "wifi parabolic range" Regards, Dana.
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    Hep please - what resistor size.

    SCR / Triac Handbook : https://archive.org/download/scrmanual/SCR%20MANUAL.pdf Regards, Dana.
  10. D

    9V LED Circuit: Only One LED Lights Up

    If you have a bench power supply, you could make a simple plot of V vs I to see how closely they are matched. If you tried 18V on them and they still not operating correctly something is bad with one of them. Note using > 12V is overstressing the leds, as they are rated for 6V. There seems to...
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    9V LED Circuit: Only One LED Lights Up

    First their series threshold to turn on is 12V per your description. But because they are exponential curved diodes in I-V characteristics they will turn on at a lower V but lower current/brightness. Because they are not matched one may have much higher turn on V so it stays off but the...
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    Need this electronic components or equivalent Plz help

    Soldering look s poor, this thru hole lead does not look like the solder wetted or wicked onto the post, or is it just my old eyes ? Where is the burn mark you were referring to ? The pwm controller chip seems to have ebay availability and here...
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    Powering projects from marine power circuit.

    I would use the buck bost for the 10 - 15 and a linear for MCU as its inherently lower noise. Also choose bypass caps wisely, lower esr better - As far as data links, if wire needed low cost optical great for noise immunity and other wire drop and induction issues. ESP32, take care in...
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    5V, 3A over-voltage circuit needed

    You mention in original post losing the reference leg to ground of a regulator. One classic approach is blow a fuse with a crowbar, scr, that shorts supply rail to ground if V exceeds a design set value. The crowbar can operate off the downstream power (while it exists) to generate the trigger...
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    Wifi woes

    Parabolic antennas work well to boost receive performance. I have used them in links > 2 miles, at eevblog I think they did some testing out to 5 - 10 miles. Regards, Dana.
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    Shortage in 3 terminals of mosfet

    Knowledge gained would be to examine the internal damage as the pics show. Plus there are variants to these failures, all the way to package blowup. But knowing the 3 pins are shorted, by any means, is limiting in gaining any specific additional knowledge..... Can you describe what your...
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    Shortage in 3 terminals of mosfet

    Failouyre mechanisms : https://www.4qd.co.uk/docs/mosfet-failure-mechanisms/ Similiar considerations - https://www.infineon.com/dgdl/s30p5.pdf?fileId=5546d462533600a401535748559c3fcd https://www.diodes.com/assets/Uploads/Auto-MOSFET-BLDC.pdf Google "mosfet failure sem images" and look at the...
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    Manhattan Style Prototyping

    Manhattan type prototyping https://i0.wp.com/www.pbase.com/daverichards/image/157055577/original.jpg Getting Ugly, Dead Bugs, And Going To Manhattan Back in the 1980s I was a budding electronics geek working in a TV repair shop. I spent most of my time lugging TVs to and from customers...
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    5V, 3A over-voltage circuit needed

    There are comparators with onchip V ref to precisely set a trip point, that driving a pass transistor or a shutdown pin on a regulator would achieve what you need. https://www.analog.com/en/parametricsearch/11391#/ Then there are these high side power switches -...
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    looking for very special push button switches

    Looks like a custom membrane or tactile actuator panel. Quote a few suppliers offer those services. Google "custom membrane switches", tons of suppliers. Regards, Dana.
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