During study , I am encountered with this two Inverter symbols .  Sometimes this two symbols are usedn in same logic circuit. Though they are working as inverter, I'm guessing there must be some charecteristic differences indicated by this two symbols.Or there is no logic to use two different symbols in same circuit.  Is this symbols indicated different kind of inverters or some different physical properties  ?
47446
See , page 2: the internal logic diagram for the MM74HC138.    The diagram shows logic inverters with bubbles at the input or at the output. Is there an actual difference between them?
19592
I started studying flip-flops recently and I am stuck at this point: At some video tutorials, people explain the SR flip-flop like this:  So they use NAND gates, producing a transition table like this: |     t     | t+1 |  S  |  R  |  Q |  0  |  0  |  INVALID |  0  |  1  |  1 |  1  |  0  |  0 |  1  |  1  |  ?  However, some other people explain the SR flip-flop using NOR gates:  (source: ) which has a different transition table. Are both correct? Why do both exist?
117146
I would like to know how to understand/analyse the circuit below. And sorry but my level in electronics is not that high and I could only tell that the opposing transistors on the left are meant to cancel any current from the input , yet I don't really understand the B stage which I think the C stage is well related to , and if I wanted to analyse the nodes around the circuit apart from (A,B,C) How can I do it ?  Is it by measuring the current on resistors/nodes?  and note that the output voltage of the circuit in node C is zero this is what it meant to be.I would appreciate any help.  Regards
37426
For 3 input XOR gate and XNOR gate, by solving the equations I got the result as in the picture.  So according to the solution the outputs of the 3 input XOR and XNOR gates are same. This solution holds good when number of inputs to the gates are odd.   For the case of even number of inputs XOR and XNOR are complement to each other.   With this assumption the answer to the circuit in the picture should be option A,B, and C. but the correct answer is D. I am confused as to how?   Thanks in advance for the help.
70801
My very basic electronics education has taught me that parallel circuits are equivalent to separated circuits. To my surprise, when I was playing around with some electronics I found the following:  Essentially I connected two red and two blue LEDs in parallel. The red ones lit up, but the blue ones didn't. Only when I removed the red LEDs would the blue ones light.  Why is this?
103305
How can I typeset the following symbol for direct current (i.e. a = symbol where the lower line is dashed)?     The image above is an enlarged version, the size I need is like =, \approx, \simeq etc.
95468
I have found some pretty complete lists (I think) of mathematical symbols  and , but I don't see a symbol for the word "and" on either list.  A person could easily just write the word "and" or use an ampersand, but I was wondering if there was an actual mathematical symbol for the word "and".  Also, if anyone knows any lists that are more complete than the ones I have linked to please provide a link.
83120
I sometimes come across with BJT symbols from which multiple lines come out of emitter or collector. Are such BJTs different kind of devices? What does it mean in solid-state level?
45646
I've seen lots of schematics use \$V_{CC}\$ and \$V_{DD}\$ interchangeably.    I know \$V_{CC}\$ and \$V_{DD}\$ are for positive voltage, and \$V_{SS}\$ and \$V_{EE}\$ are for ground, but what is the difference between each of the two?  Do the \$C\$, \$D\$, \$S\$, and \$E\$ stand for something?     For extra credit: Why \$V_{DD}\$ and not simply \$V_D\$?
56773
Could someone please tell me what the symbol ringed in red represents?     I know it has ON Switch pointing to it, but the symbol has other lables in different parts of the document.
38840
I have gone through various sources... But I am not quite sure what it is.I want an and gate and the logical equivalent is two inputs feeding to one gate and for Y=AB' the logical equivalent is feeding to one not gate and one and gate. But it is the same LUT for both AND and Y=AB'. I think we store the values as desired in the LUT. Someone elaborate on this
20847
I found on one schematic that has resistor with value 56E.  I don't know what does that mean.  Can you give me some information, please.
59450
Is it the current you have to drive in the input to get a specific, defined voltage at the output? And don't the currents cancel each other when applied to both inputs?
19731
PWM channels in certain microcontrollers such as the SAM3X8E have two complementary square output waveforms, PWMH and PWML, per channel. What is the purpose of having two waves that are the inverses of each other?
63615
I know that , a basic MOSFET contains source and drain , and either it's a NMOS or PMOS ; it is indicated by an arrow at source . But let's look at a fabricated NMOS.   Here we can easily see that either a pin is source or drain is totally depended on the connection. Without connections , this device is symmetrical . But look at the conventional MOSFET symbols .   all these symbols marking a pin as source and other one as drain. Why is that ? Why this symbols are not symmetrical as the device is?   When I work on Cadence , schematics symbols all have this types of symbols where sources are marked .But when it will be used for fabrication , source and drain will be determined by the connection , not by the symbol.
112087
I'm reading through  for the , which contains this figure on page 16:    This is of course an instrumentation amplifier that apparently uses an inverting amplifier's output instead of a ground in the lower-right corner of the above figure, but what really perplexes me is the 100 k&Omega; resistors attached directly to the noninverting inputs of three of the four amps. I don't recall seeing an instrumentation amplifier circuit in books or application notes that have them, and all of the instrumentation amplifiers I've built using the three op-amp scheme works fine without them.  The datasheets specifies an input resistance of 1012 &Omega;, which is 10,000,000 times greater than 100 k&Omega;, so it doesn't seem to add anything to the already high-impedance JFET inputs. I thought perhaps it has something to do with input bias currents, but that's just me making a wild stab in the dark.  Curiously, figure 26 in the same datasheet (page 18) shows a two-op-amp version of an instrumentation amplifier without the 100 k&Omega; resistors at the noninverting op-amp inputs!  What's the purpose of the 100 k&Omega; resistors at the noninverting inputs in the above circuit? Am I missing something completely obvious?
28825
These seem to be very similar as they both separate two operands. When would one be used over the other? Is there any difference in the math spacing surrounding them?  How would the spacing in these relate to to the spacing produced by \mathop?