All Questions
Tagged with ttl transistors
29
questions
2
votes
1
answer
188
views
Turn on/off a LED using a D-FF and a transistor
I'm trying to control a LED using some microcontroller and I designed a circuit using a D-FF and a transistor to handle it. It looks like this:
So I can control when to turn it on or of by simply ...
- 21
1
vote
1
answer
41
views
Interface higher voltage signal to 5 V pull down input signal circuit using discrete hobby components
I have a microcontroller, TTL logic that expects its input to be connected to the ground via a brake lever to tell the microcontroller that the brake has been applied. I believe it uses an internal ...
- 286
5
votes
2
answers
617
views
TTL NAND gate analysis
I was looking into Millman's Microelectronics book, 2nd edition, pp. 245 - TTL NAND Gate.
I am a beginner in electronics and was looking into this book just because of an assignment problem about a ...
- 153
0
votes
3
answers
185
views
Schottky TTL current calculator [closed]
I have a problem from university where I have to calculate the I ccl. I am a little bit confused because I don't know how to do it.
The problem says as well that Schottky TTL state is 0 logic (I think ...
1
vote
0
answers
138
views
Confusion In Fanout of Logic Circuit and Transistor
Fanout:-Maximum Gate we connect to output of any Logic gate.
so there is limited number of gate we connect the output of Logic Gate.hence there is some minimum condition required for operation of ...
- 306
0
votes
1
answer
354
views
Advantages of using 2 NPN transistor NOT gate
Is there any benefit using 2 NPN transistors for a NOT gate rather than one NPN transistor?
- 39
0
votes
0
answers
73
views
What is "level of saturation" for transistors?
This is a term I've never heard of, and it's presented on a work analysis of a ttl nor circuit. It basically says that the transistor that links the output with the ground should have a higher "...
- 113
5
votes
2
answers
602
views
TTL NOR Gate analysis
I'm looking at the design below. I am reading this webpage where the picture came from.
What I'm aiming at is the wisdom behind the design. Looking at the two transistors facing downward, I assume ...
- 317
0
votes
1
answer
250
views
TTL Gates Power Dissipation Values
I am not finding any datasheets that provide clear information about the power dissipation of some gates of the 74LS series:
08, 02, 04, 00, 32 and 86.
Can someone help?
- 181
3
votes
2
answers
3k
views
Working of a transistor in a TTL inverter circuit
I was referring to TTL inverter circuit in the book Digital fundamentals by Thomas Floyd and its working principles first proposition went as follows:
When input is HIGH, Base emitter of Q1 is ...
- 55
0
votes
1
answer
1k
views
TTL to NIM logic translation Logic Gate Issue
NIM is a standard used in nuclear physics. I'm facing an issue with a logic gate being used in my TTL to NIM translation circuit, and I'm not sure what is entirely wrong with it. For a little ...
0
votes
0
answers
113
views
Voltages at nodes in TTL logic gate
I'm trying to answer the question that has been given here.
I think I understand which transistors are on and which are not under the two different logic states i and ii.
However, what I really ...
- 33
0
votes
1
answer
1k
views
Two BJT as Switch for 24V problem with LED always on
Circuit
This is the simulation on Falstad that works:
Where it is being done that way for tests purposes, but the objective is to use a TTL signal from the encoder to send a 24V signal to a PLC or ...
- 105
0
votes
2
answers
641
views
Why is D2 switched off and T4 not in saturation mode in 7408 TTL Gate as shown below?
In the circuit, when both the inputs are high at 5V, than why is D2 switched off? Will it not draw voltage from Vcc?
Also, when one of the input is low, why is T4 not running in saturation mode? Will ...
- 1
4
votes
2
answers
19k
views
TTL, Totem Pole vs. Open Collector Output
What is the difference of these two ttl nand gates?
What is a totem pole, what does it do and what is it used for?
When connecting multiple ttl logic gates together is it better to use one or the ...
- 53
0
votes
1
answer
1k
views
4
votes
1
answer
471
views
Why are bipolar transistors often used with the base at vcc?
I often find transistors used as shown below. Note that the BJT to the left is being used in a strange configuration, where the base is being pulled permanently high.
What on earth is the transistor ...
- 1,465
0
votes
1
answer
1k
views
voltage drop across collector and emitter when using transistor as a switch
I am trying to send TTL pulse from Arduino to 8 raspberry pi simultaneously. For this, I am using npn transistor as a switch. Below is the circuit for same:
Note: MB102 is a power supply that takes ...
- 103
4
votes
1
answer
12k
views
TTL NAND gate (totem pole) current and voltage analysis
I am working on a few practice problems for my course and I am unsure about my working throughout.
hoping for some feedback and guidance from the community as it's not my strongest topic.
Here is ...
- 87
1
vote
0
answers
1k
views
How to make a multi emitter BJT transistor? [duplicate]
Im trying to create the 74XX series IC's from scratch, using just transistors, resistors and diodes. I intend to chain them together and create some logic systems. Right now i'm trying to create a ...
- 33
1
vote
1
answer
348
views
Shift register that can source +-15V?
I need to source +15V or -15V resp. on several pins (20+) using a few TTL level pins (SPI, I2C, serial) from my microcontroller. Only one of the pins will source +15V at a time, the rest are -15V.
I ...
- 11
-1
votes
1
answer
210
views
How to choose transistor for TTL
I have the following circuit, where logical zero = 0.2 V and logical one = 5.2 V. I chose KT301 (Soviet transistor) for it, but there is no such transistor in "electronic workbench" for simulation. ...
1
vote
1
answer
339
views
Using TTL logic, is it better to use a JFET or MOSFET switch for power?
Using a 3.3V (max. 8 mA) output pin off an Intel Galileo development board, I need to turn on and off a 18V DC motor. Is it better to use a JFET or MOSFET transistor?
6
votes
2
answers
14k
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Help between 2n2222 and 2n2222a?
I am thinking about ordering this:
http://www.ebay.com/itm/x100-Fairchild-PN2222A-2N2222A-NPN-Small-Signal-TO-92-Transistors-US-Seller-/171520659038?pt=LH_DefaultDomain_0&hash=item27ef6d8e5e
and ...
- 81
0
votes
3
answers
751
views
Solid-state Electronic switch for low level signals
I need a very simple circuit to connect a signal to one of two ways like this:
My com signal is actually a microphone input, so very low voltage, <200mV, how can I make a solid state switch that ...
- 507
6
votes
2
answers
4k
views
CMOS vs TTL Logic Gates?
This is probably a simple question but how come CMOS Logic Gates built from Only Transistors is completely different from one that uses TTL Logic (Like BJT's). I know BJT aren't really used anymore ...
user3073
2
votes
2
answers
1k
views
Clock Pulse from Audio Signal (Laptop Headphone Jack)
Been fiddling with some circuits on breadboard to get a stable clock pulse from an audio signal via a laptops headphone jack.
Reason 1: Other precision sig gennies are out of the budget right now
...
- 21
5
votes
3
answers
2k
views
Going from Transistors to Gates to.....IC's?
So I am trying to understand I guess what is probably a basic concept of computers.
I was taking a look at this previous question:
From Transistor to Gates
And it's accompanying link:
http://www.cs....
user3073
5
votes
4
answers
6k
views
Switching relay with a PNP and TTL levels
I can not wrap my head around the fact how I can drive a relay (24V, 160ohm) with an tip32a PNP transistor which has TTL inputs from a controller.
I can easily calculate my resistors when I use the ...
- 464