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  1. D

    Transistor as a switch

    I was fortunate enough to sit 2 - 3 desks away from Pease for several years. He was a first class "seeker". I talked to him subsequently more often when I became FAE in Boston than when I sat close to him, his attendance at seminars. My boss, Jim Moyer, was good friends with Barry Siegal...
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    1602 Display Problem

    Pin 3 typically 2 - 5V, sounds like its shorted to ground. I have used many where I operated them a diode drop below 5V, eg. 4.3V. Pot could be under display, would not be the first time I have seen that. Post a pic of the underside of the board the display is soldered into and post it...
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    AC audio signal superimposed on to DC question

    A sine with DC is a simple sum of the DC component and the AC. So you take the value of the sine at a specific phase and add the DC to it, you get a scope pic that shows the Sine shifted by the DC. If you then AC coupled that sum, out of the summer, you would recover the sine, symmetrical about...
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    Transistor as a switch

    My in accuracy or posting error, this Should read Regards, Dana.
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    Transistor as a switch

    I don't know, do not see any direct field theory equations posted. But Ebers-Moll, in virtually all EE textbooks.....says the current dumb down current operating model, has limitations worthy of discussion. Not to offend there is the Gummel Poon we all use in Spice sims. Which degenerates to...
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    Transistor as a switch

    True, also never looked at field theory in dielectrics or the chemical makeup of package plastic or..... That of course does not negate the legitimacy of models derived from physical principles. But maybe we should ask the analog designers doing 20+ bit design, heck even 12 bit over T and V...
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    Transistor as a switch

    I say that Ib = Ic / 10, the terminology is forced beta, and many datasheets spec Vcesat at a forced beta of 10. From the 2N3904 datasheet - Regards, Dana.
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    Transistor as a switch

    Pretty much agree. Its interesting though, we constantly complain about the incompleteness of various spice models, yet here we (includes me) sing the praises of an incomplete model. Like the rule of thumb we use to sat a transistor Ib = Ic / 10, but this one does not always comply - The...
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    RELAY Omron

    Not the coil. The coil is rated for 12 VDC as rated. Contacts yes, to turn on a load, seem to be rated for 5A. That would be a series connection to load. Regards, Dana.
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    Transistor as a switch

    I think the device physics support its the field in the Vbe junction that controls the transport across the base.. The region look like - As pointed out here the current controlled model is an over simplification of the bahviour. Simulators use the Eber-Moll model for accuracy, not the...
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    Transistor as a switch

    Transistors, bipolar, are V controlled devices. The classic relationship of I and V is (Ebers-Moll) - Regards, Dana.
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    ECG ON TEENSY | Needed help in circuit diagram?

    A PSOC has all the resources needed to implement the analog front end as well as filtering capabilities. https://digital.library.unt.edu/ark:/67531/metadc177242/m2/1/high_res_d/thesis.pdf https://www.hackster.io/ateeque/emergency-remote-electrocardiogram-ecg-monitoring-system-955f0e...
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    Microprocessor Generation of Summed Sine Waves with Random LF Modulation

    epsolutions, not out of your league. Here I dragged out of the onchip catalog a WaveDac, "wired" it to a pin with a wizard, wrote one line of code, a start instruction for the WaveDac, and generated a sine. What could be more simpler ? Its a breadboard full of different parts / components...
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    HAM Radio Relevance Currently and Personal Reflections.

    KB1RHB here, rarely talk, mostly listen, restore old receivers and transceivers. Go to local twice a year Nerafest, several hundred attend. Lost of nerds like me, from hobbyists to tech s to EEs to Phds.....From people just discovering resistors to designers of COM equipment. From VLF to...
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    Need a comparator but don't have one?

    One drawback of CD40106 type of logic parts is they have a very low trip accuracy for a specific valued voltage, eg. no good Vref to compare against. As well as wide sensitivity to supply V and Temperature. You can get comparators today with onchip Vref to solve that issue. Regards, Dana.
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    Milwaukee Battery Problem

    I go to the consumer affairs advocate in your state. Supply a timeline of facts, etc.. Sometimes you get help, many times no. I had some guy at a parts/service store, VIP, try to pull some BS on an inspection, "my tires discolored", supplied State with info, they directed to appropriate...
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    Sound activated halogen work light

    Yes, just google "diy sound activated", many projects, some can handle power switching needed via relay or SSR. One of many projects - https://www.instructables.com/Sound-Activated-Outlet/ Regards, Dana.
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    Best IC Assortment, both Linear and Logic.

    An alternative is to use Arduino with Block Programming language. Here is a simple example of what it took to create a V to pulse width converter, like a brightness control for an LED. The blocks on right dragged out of left vertical grouping of blocks, pins defined, and then the tool...
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    Best IC Assortment, both Linear and Logic.

    There is an alternative way of addressing this, to use a SOC as your key component. Can be used codeless to extensive code depending on what you are doing. Here is whats onchip, everything from simple gates to complex state machines. Analog as well. OpAmps, Comparators, Vref, DACs, A/D...
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    Proximity sensor issue

    Does sensor have noisy output, and PLC not using hysteresis to help eliminate this ? PLC Power supply "clean", unused inputs managed with pullups and/or code ? Regards, Dana.
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