Questions tagged [not-gate]

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1answer
51 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 ...
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3answers
93 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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1answer
95 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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1answer
83 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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3answers
242 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 ...
7
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2answers
1k 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 ...
0
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1answer
125 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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3answers
48 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 ...
3
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3answers
425 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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1answer
828 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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2answers
89 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 ...
1
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1answer
12k 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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2answers
121 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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3answers
10k 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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2answers
90 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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1answer
243 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 ...
27
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2answers
5k 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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3answers
978 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 ...
2
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3answers
554 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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3answers
670 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. ...
5
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2answers
64k 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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2answers
1k 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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1answer
179 views

empty capacitor indicator + short pulse

circuit idea: // note -> times I specify in further text are symbolic ...
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2answers
491 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?