Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [not-gate]

46 questions
27
votes
2 answers

How does a NOT gate generate power?

I know that a NOT gate always inverts its input. When the input is "ON" I can imagine the gate stopping the flow of current. But how does the gate generates flow of current when the input is OFF? Please could you explain how this happens as simply…
The King
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11
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3 answers

Why do logic gates need multiple MOSFETs?

I've just started learning about physics and electronics, and right now I'm learning about creating logic gates with CMOSFETs (Complementary MOSFETs). I'm interested in this because I'm a "high-level" programmer, meaning I write code using the C#…
Hessi-Dude
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8
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3 answers

Using CMOS Schmitt trigger inverters in quartz crystal oscillator circuit

In all sources I've seen about quartz crystal oscillators using CMOS inverters there's a note like this: But why Schmitt inverter is needed? Won't classic 74HC04 work?
bokjezd
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7
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4 answers

How can I make an XOR gate with basic components?

I am a very beginner in logic gates and electronic etc. I am trying to make an XOR gate only with the help of some basic components like transistors in the NI Multisim simulator. I have use AND and NOT gate circuits that I made and that were working…
KAMRAN HASSAN
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7
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2 answers

Why does 10k ohm pull down resistor not work for pushbutton with NOT logic gate?

I made the following circuit on a breadboard using a 10k resistor, 100 ohm resistor, LED, and 74LS04 NOT gate. I expected this to work since the input of the NOT gate is at 0 volts when the switch is not on. For some reason, this setup did not work…
shurup
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7
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2 answers

Making a logic circuit with only NAND GATES?

I am trying to create a logic circuit using only NAND Gates for this expression: (NOT Q AND P) OR R This question has really gotten me stuck! Can somebody please help?
Mathematica
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4
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2 answers

What is the use of transistor in the input side in TTL logic family?

Second transistor will turn ON and OFF if input voltage is directly connected to its base terminal. Then why a coupling transistor is used at the input side of a TTL logic gate?
tollin jose
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3
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2 answers

Why are two transistors or one transistor and a resistor used for a NOT gate?

We use one n-type and one p-type MOS transistor for a NOT gate or one transistor and one resistor. Why can't we use one transistor only without a resistor?
Ganesh Rathod
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3
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3 answers

Avalanche diode random source design

I've seen lots of examples of avalanche diode (or other reverse PN junctions) white noise sources, and before I go out and build it, I've got some questions about the design. First, my first cut at it: simulate this circuit – Schematic created…
nsayer
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2
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6 answers

How can I 'invert' a 24 VDC signal

I have a 24 VDC 'signal' coming from the same line a solenoid is being supplied from. This signal comes from a PLC. I have the need to take this signal and 'invert' it, so it can be used to drive another solenoid in a flip-flop fashion, i.e. when…
user3263740
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1 answer

what kind of transistor is this?

I'm just beginning to understand a bit about transistors and wanted to build my own NOT gate with what i thought was an NPN Transistor. When it didn't work I thought maybe i had the pins mixed up and tried every configuration possible to no avail,…
Jeffery Springs
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2
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1 answer

An inverter gate reduces the peak-to-peak of the signal!

Using a HCF4049 to invert a signal, I simply fed the input to one of its not-gates and got its output. Here is the result: The highlighted red lines is the output of the not-gate. (Yep! my analogue oscilloscope can display colors, it knows how to…
Sohail
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2
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1 answer

How to simulate a real inverter?

I'm new to digital electronics and I want to simulate in ltspice a circuit which contains a couple of 74LS04 inverters. What represents the "Test conditions" under the switching characteristics in the datasheet? All I have understood so far is that…
SebiSebi
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How Does This NOT Gate Work?

I think this question may have already been answered, in a way... But I am not satisfied. I'm reading this book about creating a NOT gate and it mentions that electricity flow from the collector to LED2 connected directly to ground stops when the…
user3704920
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vote
1 answer

Using a CPU fan to drive a MOSFET on/off

Mechanical Engineering student here. I am attempting to build my own positive air pressure respirator using a vacuum motor. I have a little CPU fan to put at the exit vent of the respirator to detect when I am breathing out, and subsequently turn…
Logan Klingler
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