Questions tagged [not-gate]

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11 votes
3 answers
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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-...
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-1 votes
2 answers
82 views

Higher input voltage to a not gate

Consider a digital not gate which its input range is 5V (5V and near considered 1 and 0V and near considered 0). What happens if we give an input of say 6.25V? Since this is component dependent: What ...
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0 votes
2 answers
108 views

Why are the resistors compulsory in this circuit? [duplicate]

When I use resistors, my circuit is working fine but if I remove them, then the LEDs in my circuit don't work anymore. As seen here the switch just sends high (red) voltage ahead Can you please ...
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  • 11
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1 answer
69 views

How to amplify low voltage back up to supply level

I have a voltage supply that provides 6 V. The voltage gets run through a complex series of transistors, and the output is around 1.5 V. This is too low for the rest of my circuit to work with. In ...
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0 votes
1 answer
54 views

Sn74hct04n - always pulls to Ground

I have a very simple circuit in which I make use of an SN74HCT04N logic inverter to pull a line to GND when a button on 5V is pressed. You can see the circuit in my, unfortunately very bad, drawing. ...
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0 votes
1 answer
107 views

A simple circuit of NOT using a buffer

First of all, I am new to the area of electronics and I want some help to stuff that may sound to you a little obvious. I've seen a circuit using transistor that is used as a NOT logic gate, as in the ...
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0 votes
1 answer
359 views

How does ground affect a circuit with a diode, connected to the power source which is connected to a ground and an LED for it to act like a NOT gate?

I was searching for a way to use diodes to make a NOT gate. I found a circuit online and simulated it in an application. The configuration has a battery (1),where the negative terminal is connected to ...
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0 votes
2 answers
157 views

What's wrong with this circuit?

Hello stack community! I've just started to learn about logical gates for my university course. I'm trying to design and run a simple circuit with not gates in Proteus as below: But I'm facing with ...
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3 votes
2 answers
307 views

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?
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7 votes
4 answers
2k views

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 ...
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0 votes
1 answer
162 views

Is a resistor compulsory in a NOT gate made from an NPN transistor?

I am making a NOT gate using a BC337/BC547A transistor (tried both) and I have made this circuit (image shown below) using a simulator: This is working properly. However when I remove the resistor R1,...
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2 votes
1 answer
104 views

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 ...
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0 votes
1 answer
248 views

NOT gate power consumption

Given this NOT gate schematic using a transistor, and assuming the power supply is a battery, won't flow from Vcc to ground discharge the battery when the transistor is on? If yes, are there any ...
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0 votes
2 answers
575 views

Why is my 74HC04 not inverting my input?

My Situation I have this: https://www.tinkercad.com/things/gUv4whDvcO3-fabulous-crift/editel?tenant=circuits Or if that fails: Schema (I think this is right, I have not used schemas much before as I ...
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0 votes
1 answer
235 views

Class D Amplifier is not working?

I am building a class D Amplifier, I have to build my circuit but, overall in the circuit, My hex inverter is not working. when I am providing a digital PWM signal from the LM393 comparator to the HEX ...
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0 votes
1 answer
89 views

CMOS NOT gate output

Can somebody please tell me why do we have those tiny random spikes on the output signal? And why does the input wave behave like in the picture when we reduce the frequency of the noise source to ...
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0 votes
2 answers
271 views

Double single-transistor logical inverter not working as expected

I had a 5V-powered circuit with a single-transistor (BC547) logical inverter in it, it worked wonderfully. Then I also needed a "buffered" version of the signal that goes into that circuit, ...
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1 vote
2 answers
218 views

NE555 in a light detecting circuit

I'm completely new to electronics but my degree gives me a basic course with a project at the end. I built this small circuit to detect when a light is shined on the LDR to turn on an LED so ...
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1 vote
2 answers
285 views

Understanding Resistor Values in TTL NOT Gate

I've been teaching myself electronics and a current approach I am taking, is to be able to describe the purpose of every element in the standard TTL NOT gate: Circuit lab TTL NOT Gate At this point ...
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0 votes
1 answer
314 views

1 TTL IC -> inverter + 2-input NAND + 3-input NAND

I came across this question in my homework: Implement the following gates using only one TTL IC: one inverter, one 2-input NAND and one 3-input NAND. The type of IC they're talking about has 14 pins,...
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  • 59
1 vote
3 answers
260 views

How does a digital logic NOT (inverter) gate work?

I've read several so-called explanations on the web of how a NOT gate works, but they all explain WHAT it does, not HOW it actually works. I know what it does. Consider this schematic of a NOT gate: ...
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2 votes
1 answer
120 views

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 ...
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  • 304
0 votes
1 answer
115 views

amplifying out signal of germanium diode

Hello Dear All. Please see the attached pic. As you see i have used a germanium Diode and am going to drive to a logic gate (74hc14N). But the forward voltage of diode is 0.3v, whereas the 74hc14N ...
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  • 1
1 vote
3 answers
621 views

Maximum resistor values for transistor inverter (NOT gate)

I have my circuit configured this way because I'll be hooking up my 8051 microcontroller GPIO pin to the point where three resistors (R2, R3, and R4) intersect, and the microcontroller only outputs my ...
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7 votes
2 answers
2k views

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 ...
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  • 645
0 votes
1 answer
179 views

What is the truth table for a logic NOT gate with two inversion bubbles?

I am currently reversw engineering a PCB and it contains a D-type register chip. The chips internal circuit diagram shows a NOT gate with two bubbles on it both in the front and the back. My question ...
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  • 103
0 votes
3 answers
85 views

Why are rise and fall times of a wave going through series inverters not dependent on first inverter?

I've been intrigued lately by the observation that if enough inverters are placed in series the rise and fall times of output waves become invariant to the delays of the input inverter. The chain gets ...
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3 votes
3 answers
702 views

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:...
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0 votes
1 answer
1k views

Need help with NOT Gate oscillator circuit

Sorry, if the question seems silly, but I really need someone to help me understand the below oscillator circuit. How can the oscillation begin, if there are no initial conditions? All analysis shown ...
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0 votes
2 answers
119 views

Not Gate switching

Hello I'm new to electronics. so i've created a NOT GATE with an NPN transistor like that Everything works fine for now but what i want is adding a PNP transistor that will be triggered by the NPN ...
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  • 17
1 vote
1 answer
17k views

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 ...
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  • 125
1 vote
2 answers
192 views

LED in NOT gate confusion: LED voltage drop vs transistor voltage drop

I saw a schematic for building a NOT gate, it worked, but there's something I don't understand. Here is a pic of what I did (sorry about my finger hiding the push button) If I push the button, the ...
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8 votes
3 answers
16k views

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?
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  • 105
1 vote
2 answers
150 views

A NOT gate with gradual changes between state

I have a simple NOT gate circuit with the following arrangement. LED D1 will light up by default. If I push SW1, the transistor Q1 will activates and D1 will be turned off. This NOT behaviour works ...
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  • 319
0 votes
1 answer
396 views

Explaining the need for two transistors in Not Gate

I was reading: http://www.cs.bu.edu/~best/courses/modules/Transistors2Gates/ To teach myself transistor logic, but I have some questions on what I believe are unnecessary strucutres (most likely ...
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27 votes
2 answers
7k views

How does a NOT gate generate power? [duplicate]

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? ...
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  • 381
0 votes
3 answers
1k views

Analog NOT gate [closed]

I am pretty new to electronics and was wondering how you could get a NOT gate for a 9v battery. I understand that it can not make power at the output when there is no power input, so it would probably ...
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2 votes
3 answers
683 views

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 ...
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0 votes
3 answers
868 views

Dual Mosfet Not Gate Getting Very Hot, Critique Circuit

I have put together this circuit from parts I had lying around, It is to invert a normally closed momentary switch to behave like a normally open. The switch is for a car and toggles a tail light. ...
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6 votes
2 answers
73k views

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?
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0 votes
2 answers
3k views

Transistor Based NOT Gate Not Working?

I Followed The Following Circuit For The Logic NOT Gate from This Website http://www.northdownfarm.co.uk/rory/tim/basiclogic.htm Here is My Circuit Which is Intended to Perform The NOT Function and ...
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0 votes
1 answer
190 views

empty capacitor indicator + short pulse

circuit idea: // note -> times I specify in further text are symbolic ...
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4 votes
2 answers
701 views

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?
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