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  1. F

    the finer points of electronics - II

    so it's Ve = Vc - Vbe? ok... i missed that from just reading from wikipedia... i read the voltage on the load is *mostly* is constant for most of the operating current range... then again the examples from wikipedia has the load on the collector side... collector side, then...
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    the finer points of electronics - II

    well,  emitter in saturations is still slightly bit higher... (Ie_sat = Ib_sat * (1 + hfe))
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    the finer points of electronics - II

    answering my own question again: it just struck me, but maybe the capacitor was not charging not because of properties of currents in collector and emitter for any NPN, but because i've been thinking in terms of conventional current... Let:     Q be a sub-circuit of an avalanching transistor...
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    the finer points of electronics - II

    i'll solve the specific circuit problem on my own... although, i would like an answer on the first question... when switching, is it better to go with the emitter on NPNs and the collector on PNPs?? do their electrical characteristics differ more than slightly higher currents?
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    the finer points of electronics - II

    i'm asking as i've been working on a design that to my understanding should've worked. i have a generic NPN restoring the supply voltage and feeding it's emitter output to a 2N2222 parallel to a charging capacitor for a delayed avalanche. somehow the avalanching only works when i swap the 2N2222...
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    the finer points of electronics - II

    alright, continuing the series... another question i would like to as is on NPN BJTs, would it be better to put the load on the collector side or the emitter side?? in schematics, i almost always see it on the collector side (Ic = hfe * Ib), but the emitter side also works and when doing plain...
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    are BT2222 transistors the same as 2N2222

    awesome! thnx.
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    minimum reliable low currents

    i need to know what is the lowest current that is reliable for cases such as: a.) charging a capacitor b.) when the current is being read by an instrument such as an ammeter c.) logic signals what i mean is that even outside normal conditions -- exposed to hot summers and cold winters, being...
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    are BT2222 transistors the same as 2N2222

    are these NPN BJTs: http://pdf1.alldatasheet.com/datasheet-pdf/view/17918/PHILIPS/MMBT2222A.html the same as those 2N2222 that has been around for since forever? can i trust that the reverse active and avalanche breakdown profiles are the same??
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    comparator for DC voltage

    ok i actually just realized the flaw after i last posted. i thought of mentioning it, but i thought it will have you guys think that i am trolling. (i actually just checked again for additional posts from you guys) yes, hero999 there needs to be a common ground here for this to be a universally...
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    RF - separate transmitter and transceiver antennas for half duplex

    i was wondering why is it, for just half duplex systems, don't we have a dedicated transceiver and a dedicated transmitter antenna. ok, just hear me out... assuming we are using grounded monopoles, we can have a resonator connected to a diode whose anode is connected to the transmitting...
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    comparator for DC voltage

    you know what i'm talkin' about... anyways, just in case somebody stumbles upon this simple thread in the future, i'll attach a more concise diagram:
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    the finer points of electronics - I

    also, why i am convinced that sometimes it might be helpful to consider "pulls" is that i see a lot of voltage supplies apparently provides negative voltages.
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    the finer points of electronics - I

    ok, i guess i lose here... in all cases "conventional current" and the idea of 0V grounding that comes with it abstracts all cases when it comes to passive components. in active components as long as it is only immediately in series with a passive component, then it *should be safe*. if 2 or...
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    comparator for DC voltage

    no, i was reffering to a "passive" comparator, sadly also being a very limited one. there's very little voltage drop and current used in your "active" comparator... it's something very discrete that can be added with very little effect to the rest of the original circuitry. mine is something...
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    the finer points of electronics - I

    uhhh... nobody's explaining this satisfactorily... c'mon... i need to know so i can ask further questions about semiconductors and VH electronics... EDIT: "VH speed electronics" forgot the "S"
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    the finer points of electronics - I

    so, looking at the attached diagram, is there a "pull" on the cathode side of the capacitor or a push from the other side?? or both? if it's a little hard to explain, then tell me how it happens in actual physics, not in conventional currents... i need to know, because, in the future, i will...
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    the finer points of electronics - I

    ok so i have questions with electronics that doesn't seem to be covered by tutorials that i've scanned throughout different websites, or i just don't want to read through a lot of material to find that small footnote that i needed to find. i'm basically going to be posting a series of threads...
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    a circuit that cuts off current when voltage drops from a given level.

    ok this is my solution... though i'm not sure it'll work as i don't know if ground actually "pulls" into it, or is everything a result of positive voltage pushing everything in.... in terms of conventional current... "R_z" limits the current so the "Z" zener diode can produce a voltage...
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    can an ammeter damage zeners??

    so i got this small circuit that plugs to the mains as power source. as for its DC converter, it's one of those transformer-less ones that drops the voltage with a resistors and filters before rectifying and smoothing it. the ones that can only deliver small currents. well, after that, it uses...
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