Questions tagged [latch]
A latch or flip-flop is a circuit that has two stable states and can be used to store state information. However latch is normally used to describe a simple storage device while flip-flop is normally reserved for clocked devices.
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Tie an input of an AND gate to its output
Let's say we have an AND gate and we give 1 as one of its inputs and we tie the other input to the gate's output.
What will happen?
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Triggering an SR Latch with multiple reset lines
Ok, so I'm relatively new to electrical engineering having worked on the software side of life in the past. I'm trying to work a simple SR Latch where only one output is enabled at once. To do this, I'...
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Latch is stable with competing capacitors?
I inherited the attached design as part of a work project. This is a latch which is meant to hold the high-voltage side of the system in the powered on state when a momentary power button attached to ...
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Is this circuit correct and safe to bypass my latch circuit, turning on the load every time I connect it to 5V?
I have this working on/off latch circuit below that works on a 8.4V battery.
I can charge and bypass the battery when I connect the circuit to a 5V charger, while still providing supply to the load ...
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First time designing an SR latch; I'm using it to control the enable pin on my eFuse IC. Just want to know if I'm overlooking anything
I just finished designing my rectifier module that has a built-in voltage monitor IC and an eFuse IC.
Its purpose is to convert the 3-phase AC output from my wind turbine and use it to power my USB ...
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Transistors falsely latch with EMI
I have a very basic NPN - PNP latching circuit:
[Sorry for the upside down image]
The latch initially is off, and when the op_amp_Signal_and_latch turns on, the ...
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ESP32 power latch circuit react on low and high (reed switch)
I am currently building a door sensor with an ESP32 and a reed switch.
My code is working with the deep sleep functionalities of the ESP32. With its help I can detect a falling/rising edge and wake ...
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Push button latch circuit - switch issue
I have built a single push on/off latching circuit as per the diagram. It runs from 12 V.
It works, but the issues I have is that first, it is already on when I connect power, it should start off, ...
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D-type LATCH output when minimum clock/enable pulse width is violated and input/output are the same [closed]
Can the output of a D-type latch go metastable when:
There is a minimum CLK/ENable pulse width violation
The input and the output of the latch have the same value?
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How to make a D-type latch not start in SET condition by itself?
I have this schematic to digitally start and stop a power supply of a Raspberry Pi, and I want to be assured that the latch doesn't start by itself in the ON state when I apply power.
Of course, if it'...
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Question about T flip-flop
I am trying to implement a switch that works like the description in the picture. In my research I came across the T flip-flop, however a T flip-flop requires a clock signal. I don't have that.
Is ...
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How do I model switches in Matlab/Simulink?
I am trying to model different types of switches in Matlab/Simulink. There is this type of switch that I can't find a name for or design. I am not an expert in digital logic, I only have the basics ...
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Is it possible to combat SR Latch oscillation or there are better alternatives?
I need to store a bit value and then ignore any attempts to store/change it again until it's reset by another signal. So I figured the SR Latch is suited for the task. However in my project there is a ...
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555 timer diagrams Q/Q bar confusion
I've seen this in several places and am perplexed. First, I thought that the output of an SR latch was Q, and the inverted output, or 'not Q' is shown as either Q with a bar over it or denoted with a ...
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Is the invalid state of an SR latch also undefined?
I understand that if both the Set and Reset inputs of an SR latch are high, the output of both Q and Not-Q is low and this is considered an invalid state.
But in this situation is the output also ...
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How does electricity flow in this SR latch from Petzold’s Code?
I am confused as to how this circuit is complete and hence how electricity flows through it.
Petzold explains earlier in the book that the V refers to a battery connected to ground the way in which I ...
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SR latch effect which only requires one GPIO
I have an STM6821TWY6F watchdog IC for my MCU. When the MCU gracefully goes to sleep it will disable the a watchdog to prevent unwanted wake ups. The watchdog was designed to look for an oscillating ...
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How to let microcontroller power itself?
I'm trying to create a circuit where a button press results in a microcontroller booting up and sending a wifi request. I'm relatively new to electronics, so likely have a big knowledge gap.
Similar ...
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How does a D-latch work in this condition?
I think that in a D-latch the Q+ (the next state) and Q'+ (the next state and prime) must be different.
But when the {Enable D Q} = {1 0 1}, the result is ...
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How do I create a digital timing diagram based on D flip-flop signals?
We are constructing a D flip-flop using 2 latches and a control-signal coming from a clock.
The flip flop looks like this (x1 and x2 are connected to two switches, L1 and L2 are standard latches ...
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How to turn ON/OFF NE555 using a pushbutton switch that is already to ground?
I'm building a circuit for my motorcycle to replace a damaged indicator module.
It runs off a NE555 to turn on another NE555 in astable mode to flash the bulbs.
The switches on the bike are push ...
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Bistable memory cell with paired buffers instead of paired inverters
Bistable memory cells with paired inverters are very standard and basic building blocks (was used in Intel 8086 for example. ) But why not use paired buffers instead?
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Why doesn't t-latch go to infinite state switching?
I've tried to build a T-Latch with NOR and AND gates in an emulator, but it causes an infinite loop.
Initial state, waiting for clock
Simulating clock impulse (the second switch)
After that it goes ...
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How can SR-Latches store data over time?
My understanding is that the storing part of SR-latches boils down to having a wire loop. Ostensibly, the idea is that if there was current in the loop a second ago, there will still be current in the ...
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WS2813 LED data permanently latching on power-on
I'm running into a problem where WS2813 LEDs 'latch' data permanently on start-up sometimes. The issue is sporadic, and random data is latched (RGB segments are enabled at random brightness levels on ...
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How do I detect a button press between MCU loop function calls?
Currently, I have a few buttons connected via an I2C shift register, hooked up to an MCU. Super simple, so not sure if it needs a schematic, but I can share one (and any other details) if needed. I'm ...
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In SystemVerilog, will assign a variable to itself within an always_comb block generate a latch?
In SystemVerilog, always_comb blocks must always specify the value of all the signals within them for all possible case branches ...
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Can I digitally open a circuit?
As a basis for a low power project, I want to render the useless machine not useless
https://www.youtube.com/watch?v=Z86V_ICUCD4
A useless machine is a simple mechanism that powers up when a switch is ...
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Weird waveform of a digital latch
I am simulating on ADS.
As you can see, the V1 goes high at 9n sec.The clk has first rising edge at 10n sec.
Why does output V2 not go up at the 10n seconds? It goes up at 20n seconds at the second ...
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SR latch circuit with ESP8266
I want to keep some state during a deep sleep of an ESP8266. To do this I used the following SR latch circuit:
It works well. The only change I made is that I used 2N2222 transistors.
The only ...
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Soft Latch ON-OFF with support of DC High Voltage side, compatibile with Arduino or any Low Voltage MCU (with schematic)
First Schematic
I'm trying to implement this schematic that I found in this interesting article (Soft Latching Power Circuits). This is a circuit can substitute a mechanical on off switch, and use ...
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24V input shutdown-latch - is it a good idea?
I want to protect my circuit by adding the ability to the MCU, to turn-off the power supply (and by this also turn itself off), in case of certain failure conditions are met. One of it would be ...
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What kind of latch would be best to continuously store and feed in a series of inputs?
So I've got an assignment where I've two buttons and LED screen. One button inputs a '1' and the other a '0', and when four inputs are detected the screen displays the number eg. If I typed 0011 it ...
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Toggle latching IC to replace relay
I need an IC on which pins stays in same state after power reset. How it's called? I don't want to use relays.
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Unclocked NOR gate SR latch not latching [closed]
I am starting to learn computer architecture and decided to try building an SR latch using NOR gates and without a clock (basically copying this video) on a breadboard.
My circuit is pictured, it is ...
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Doubt regarding SR latch
I am having trouble visualizing an SR latch intuitively. Here the two outputs \$Q, Q'\$ both are dependent on each other,so how will the two function at the same time?
Let me break it down. Suppose I ...
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How do I make a NAND SR-latch with transistors
I'm trying to make a NAND SR-latch using only transistors, by combining a schematic for a NAND gate and a schematic for an SR-latch. The resulting circuit looks like this:
(One thing not shown is ...
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Switching between power sources part 2
So I'm trying to switch between two power sources, a 24 V battery and a 24 V power supply, I'd love to use the circuit mentioned in a another thread. Switching between two power sources
I am having ...
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How to understand this combinational cyclic circuit made of interconnected SR latches?
I'm trying to understand the following circuit, or better said, what must be the approach to analyze other similar ones:
What I'm doing for now is forget about the clock signal and the ...
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Latching an analog signal on a trigger event
I am looking for sort of an analog equivalent of regular digital latches. I want it to mirror its input (voltage) to its output (voltage, with or without gain) only at a trigger edge/pulse and ...
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Does an eFuse exist that latches off immediately (and does not reactivate) in case of a short-circuit?
I've just discovered eFuses (from Texas Instruments + Toshiba + STMicro).
In case of a short-circuit on the output, MOS can be disabled in 150-500 ns by detecting a surge of current (called "fast-...
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Latch the values generated by a 4-16 line decoder
I am using a 4 to 16 line decoder to convert a 4 bit number from arduino/seeed/ESP32 to drive circuits like RGB leds which would otherwise use up all my pins. There are some problems with this ...
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Finding a pass-through demultiplexer with latch/register on output
I'm currently working on an Arduino project with lots of digital IO (21 outputs, 8 inputs) and no analog IO. This is more than the number of digital pins on an Arduino Nano, so I started looking at ...
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To turn a ratioed circuit into non-ratioed circuit, what should be the transistor sizes for proper operation of this circuit?
The circuit is at the bottom. I know it is a ratioed circuit however, how can I convert it to a non-ratioed circuit without adding two more PMOS transistors between Vdd and the other PMOSs. Also, what ...
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Identification of a circuit element
Here is the image:
What does the triangle with a bubble on one of its sides represent?
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Is there a simpler way to latch a supervisor?
I’m currently designing a Li-Ion powered ESP32 circuit.
The ESP32 has a minimum operating voltage of 3 V. So, my instinct is to use a 3.1 V supervisor to keep the ESP32 within an acceptable range.
...
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Valid Use of Voltage Divider Supply?
I know it's not a good practice to use a voltage divider as a power supply, but I'm considering it for an unusual circuit. Is this a good use of a voltage divider or is there a better way to do this I'...
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How enable for latch converts to clock in flip flop [duplicate]
Latch has enable signal and we cascade latches to make flip flops. How enable for latch converts to clock in flip flop.
I mean how and why enable driven latches form edge triggered flip flops. Why ...
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How to make this T-flip-flop circuit
I am trying to make a T-flip-flop circuit with a relay, which would:
toggle on a button press (12 V) [default state: off]
allow control from an external micro-controller (optocouplers)
allow ...
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How to stabilize this CV triggered toggle (555 timer latching switch) when fed with two gates?
I created the prototype for a modular synthesizer module. The project goal is an AND gate that is fed with two control voltage inputs (A and B with an Vpp around 5V). There will be two outputs: the ...
