All Questions
Tagged with ttl integrated-circuit
26
questions
0
votes
1
answer
277
views
Failsafe circuit for a bistable latching solenoid
I am new to embedded circuits and working on a problem with which I need help.
I am using ESP32 soc for controlling a bistable valve using DRV8833 driver module. Please refer to this link for valve ...
- 101
2
votes
1
answer
137
views
74HC74D initial output value after power up
I use a touch sensor (Active Low) to light up a light bulb. here I've used a 74HC74D D flip flop to turn on an off the bulb with the sensor pulse (sensor output is active low which is then converted ...
- 335
0
votes
1
answer
73
views
How can I find reverse current of 74lsXX integrated circuit
I'm using 74lsXX ICs for my 4-bit computer. I noticed that 74XX ICs have reverse current at the input; I know that the output of the IC allow the reverse input current flow back to it.
But I'm a bit ...
- 165
1
vote
1
answer
322
views
Why does the 74LS32N behave like an AND gate?
First of all I am a beginner.
I am practicing with the 74LS32N (OR Gate) IC , I noticed that it behaves like an AND gate instead of an OR Gate.
Only when both the inputs are 1 , the output is 1 , (Led ...
- 11
0
votes
1
answer
184
views
74HC08N doesn't latch [closed]
I am using the 74HC08N chip. Why doesn't the first AND gate latch itself?
I have connected the output of the first AND gate to its own input.
I have used two resistors, the one on top is a pull-up and ...
- 11
2
votes
1
answer
401
views
74LS47/74LS247 BI/RBO-pin usage
I am currently playing around with a 74LS247 BCD to 7 segment decoder. The basic usage for decoding works perfectly fine.
But I would like to test out everything this IC has to offer including the ...
- 21
0
votes
1
answer
712
views
CMOS vs TTL power and impedance
I need to compare and contrast a CMOS IC with a TTL IC. I've chosen a quad 2 input NAND gate IC, 7400 for the ttl version and 4011 for the CMOS. I'm having a bit of trouble with 2 of the requirements.
...
- 21
1
vote
3
answers
3k
views
The circuit with 74HC138 is working, but with 74LS138 it is not, why?
I used 74HC138 in the first circuit and 74LS138 in the second circuit.
Only the one with the 74HC138 is working.
Why?
- 31
0
votes
1
answer
88
views
Are there combo gates XOR followed by AND? (4-bit identity comparator)
Is there no 4 bit identity comparator in TTL or CMOS? It could fit into a DIP-12 package as all it would have is 4 XOR gates for selectable invesion and 1 4-way AND gate.
OUT := (A1 xor B1) and (A2 ...
- 1,541
9
votes
3
answers
7k
views
Using HC/HCT, AHC/AHCT series logic
I am builing a circuit, and i need to connect a few different IC's (obiosly). My circuit is based on 5V TTL logic and i found a part that is made only in AHC/AHCT variant.
So let's take it from the ...
- 307
0
votes
1
answer
609
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,...
- 59
0
votes
3
answers
1k
views
TTL IC logic high output doesn't reach high enough voltage
I've been having a problem trying to build a breadboard circuit.
The problem being, that some IC high outputs doesn't reach a high enough voltage, staying around ~2V. That is not sufficient for a ...
0
votes
5
answers
1k
views
RS485 IC Termination Resistor Configuration
I've made a mistake on a design, that went into production...
It was built like the drawing on the left, with R702 to 5V and R703 to GND, it should have been backwards... like the drawing on the ...
- 528
10
votes
2
answers
2k
views
How to manufacture chip on board?
I am a developer of a cheap product and i have no experience in mass production. Device is fully functional and represents a single sided PCB, a microcontroller, a bunch of diodes and a few passive ...
- 340
1
vote
3
answers
251
views
Multiple Demultiplexers In Series
Basically I need some demultiplexers to switch between 24 outputs. The data inputs would be connected to counters for the addresses. I'm currently using 74ls138 3-8 line demultiplexers. Is this ...
- 11