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    Oscilloscope samples/sec and memory depth parameter

    Unlike an analog scope a DSO is constantly acquiring data. When a trigger occurs a frame of the data is captured, frame size a f(sample rate). Then scope displays the frame. Middle of frame is trigger point, the sample where trigger occurred. So you see before and after samples of the waveform...
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    Unknown chip that looks blown

    Contact manufacturer and see if you can get a replacement part ? Is sun still in business or absorbed by another company ? Any groups.io support site for obsolete sun stuff ? Any mechanics sites you can post on looking for info ?
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    Unknown chip that looks blown

    Is that a hole blown out of chip top or something you can scrape off to get a good pic of the markings ?
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    Transient voltage suppression

    https://assets.nexperia.com/documents/application-note/AN11160.pdf https://www.nutsvolts.com/uploads/wygwam/AN11160_Designing_RC_Snubbers__NXP.pdf https://www.cde.com/resources/technical-papers/design.pdf The above might help.
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    HAM radio operation

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    IR Spectrometer Project: Is This Project Within My Reach?

    Take a look at Melexis for IR sensors, might be a possibility there. https://www.melexis.com/en/products/temperature-sensor-ics
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    Simple home project

    If I read this correctly the leds are all operated in parallel ? Therefore each has a built-in R to balance current ? https://www.stanley-electric.com/pdf/en/products/support/TN003_e.pdf
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    Simple home project

    Have you measured their current consumption when powered by batteries ? Clearly you want to operate them to their design ratings, eg. run them at design current levels.
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    Math Severity as applied to Serious Electronics

    @hevans1944 I left discrete logic as well as fast as I could. If you want parts that handle both analog and digital, and further have fabric you can easily create your own components, take a look at these. Multiple copies of these components (a component in PSOC land is an on chip resource)...
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    Setting up a Common Anode Dual LED with one reference point.

    R1 represents the output drive Z from the cmos gpio, a crude estimate based on a processors min max Vol Voh at speced current ratings. Forcing it to 0 ohms still problem remain, green not shutting off if glow issue there with actual parts.
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    Setting up a Common Anode Dual LED with one reference point.

    The only "tricky" part is with the newer highbright leds even at low V's a few uA will cause a glow, so a check for that makes sense. This shows the Green LED, when "off", has .75 mA thru it, its model has 2.1V at Vth. So looks to be a problem getting it "off". RED led model's Vth is 1.7V.
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    Setting up a Common Anode Dual LED with one reference point.

    Rough mockup. Note if chg pin goes tristate this leaves one led on, so not suitable solution. Note pin V max of 4.8 for case driving high but with load.
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    Small circuit design

    Do not know, cant speak for "most"..... Just use a current limited supply/charger. If using a bench supply set it's V then short its output and set the current to a limiting value. Its a great way of powering up circuits you wire up on a protoboard and making sure they dont get fried due to a...
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    Best approach to sweep 410-525 MHz? PLL/VCO vs ramped timer vs sweep-IC?

    DDS - https://www.analog.com/en/parametricsearch/2419#/ Analog Devices also have oscillators and PLL based synthesizers. Regards, Dana.
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    Small circuit design

    A classic fast acting circuit is a crowbar circuit to blow a fast acting fuse. https://www.electronicshub.org/crowbar-circuit/ https://www.onsemi.com/pdf/datasheet/mc3423-d.pdf...
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    Small circuit design

    Cheap chargers do occasionally fail, with no output to unregulated out of spec high V out. Couple that with slo blow delay certainly possible to fry LEDs. Its a roll of the dice.
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    Small circuit design

    It could be your charger has current limit, if decently designed. If you use R you rely on charger design for safety and to prevent LED burnout. And if charger puts out more V than you have LED current changing as well, eg. not regulated. If you use LM317 definitely need a heatsink on it...
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    Small circuit design

    Here is a possible consideration, but w/o protection circuits : https://www.diodes.com/datasheet/download/BCR420UFDQ-BCR421UFDQ.pdf
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    Small circuit design

    Fuse blow times (ChatGPT) - Seems like upstream components could be challenged with slow blow fuse protection.
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    Small circuit design

    No, maybe.... Here is a rough sim comparing R vs LM317 solution The above all nominal T and component tolerance.
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