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5

First of all, I like the title of the question, "What makes a circuit Digital" ;). The world around us is analog so the electronics started with exploring the analog components like the ones mentioned by you resistors, capacitors etc. The need for digital circuits was realized when we started building devices like computers, started storing information ...


4

There is a far neater way to make a multiplexer, using a vector. Example: module mux( input wire a, input wire b, input wire c, input wire[1:0] sel, output wire y ); wire [3:0] mux = {1'b0,c,b,a}; assign y = mux[sel]; endmodule In this case you assign your outputs into the variable 'mux' and then the output will be the sel'th element in the ...


4

The size of the box is limited by the connectors so it is a reasonable enclosure and layout for a splitter type box. Without more information about the circuit it would be hard to say anything else. The spacing of TTL's is fine (if it works), if this is manufactured in quantity it is unlikely your client will spend the extra $.03 a unit for DIP sockets so ...


3

That is a terrible schematic. See this description of how to draw a proper schematic. In any case, your primary problem is that you don't seem to understand that when it is conducting, the emitter voltage of an NPN transistor can never be higher than its base voltage. In fact, it will be lower by at least 0.65 V. You're driving the base of Q1 with a logic ...


3

While using the x value in a simulation might be used to identify unexpected behavior, such a statement will not make sense if you synthesize your code to a gatelevel representation. And one-liners might be pretty, but they make the code more difficult to read. Also, the constructs may not be correctly identified by the synthesis tool, resulting in ...


3

If your MCU has an on-board comparator that can be configured to generate an interrupt, then you can simply use it. Many MCUs have such functionality. Otherwise you can simply add an external comparator such as 1/2 an LM393 or a more modern part if you need very low power. You need a voltage divider to set the threshold- in your case you might use 1.20V ...


2

Digital means having or using discrete or discontinuous states. Modern digital electronic systems are usually binary (employing logic with two states) but ternary (3 state) systems have been built (as have a few systems with even more digital levels per digit. In a binary 2-state system the two levels can be considered to be: high/low 1/0 on off ...


2

I doubt any such database exists (finding it and searching it sounds like a lot of work), but if you (skillfully) do a parametric search, there are very few families to search in so it only takes a couple minutes to scan the few pages of part numbers. The 74xx02 series is not what you want The 4001 series is not what you want The (ancient and probably ...


2

Only if an input could be left floating. For example, if you select between several outputs to a single input, all analog inputs are tied to something (or you believe they can never be selected) and the mux is always enabled then you don't need a resistor. Chances are that if you are using it as a digital de-multiplexer this condition won't be true and you ...


1

Just add this low-pass filter after the gate, and compare the readings you get: simulate this circuit – Schematic created using CircuitLab


1

First, you need to tie unused inputs (2A, 2B, 3A, 3B, 4A, 4B) to ground. Leave unused outputs floating. HCMOS inputs tend to float to a mid-level "metastable" voltage which causes much higher power consumption in the chip because the input transistors are staying in their active region. Second, you're just using the AND gate as a buffer, while you have a ...


1

"Digital" and "analogue" are sets of design techniques and circuit interpretations. Both are simplifications of the real world focused on particular sets of properties. You've asked as a clarification comment: How do you take an analog circuit and make it digital? How do you get it stop treating a signal as analog and start treating it as digital, ...


1

If you're willing to use a pullup or pulldown, the 74XX125 and similar devices will reflect the inputs on their outputs if the enable line is asserted, and go high-impedance if deasserted.



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