Questions tagged [latching]

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25 views

How to add a MCU signal to turn off this push button mosfet-based latching circuit?

I’m using this circuit to turn on and off an Attiny85 and a led driver with the push of a micro switch. My circuit is powered by 7.4V battery. In the “load” part of the circuit there’s a voltage ...
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0answers
23 views

Can't find suitable Bistable/Latching 12V DPDT Relay

I have a 12V actuator that is controlled by a 12V programmable timer. So my pulse is either power or no power. I am using a regular 12V DPDT relay which works fine. However, I would like to use a ...
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2answers
364 views

What's wrong with this latching relay circuit?

I've been told that this relay circuit should latch. I built it and it does not. I want the LED light to stay on after the N.O dP switch is is closed and then released back to its N.O. state. Using 24 ...
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0answers
36 views

pmos latch switch

We have a power distribution board for our robot that is responsible for switching power to various modules (controlled via stm32 gpio). The first implementation was pretty simple. we used a high side ...
3
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1answer
47 views

Problem with SCR latching circuit

I put this circuit together to demonstrate latching properties of SCRs but I'm finding that the SCR doesn't behave as I expected it to from the datasheet values. Specifically, I found that in the ...
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1answer
117 views

Want to replace push-button with IR receiver

In the diagram below I want to replace that push-button switch Sw1 with IR receiver, I tried a lot with different combination with IR receiver and tried with transistor but I failed, so, please how ...
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1answer
36 views

Toggling 9A with ATtiny85 single-button-latch

I'm trying to use a nice one-button On|Off latching setup on ATtiny85. See for details the last one of these four: http://www.technoblogy.com/show?VOO In a low-power set-up on my breadboard this is ...
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1answer
61 views

3V Soft latching switch

I apologize if this has been asked before but the answers I found are all over the top for this simple latching application. I'm looking for a very compact solution: 1) 4.5 volt dc, 3 stacked hearing-...
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3answers
60 views

Persistent Mechanical Feedback

I am looking for a device (preferably in a small form factor) that can provide feedback for the user even after the power has been removed from the PCB (No, I don't want a battery powered solution.). (...
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0answers
51 views

How to do a latching circuit

I want to make a latching circuit with a relay. My problem is that I do not have a NO switch in the "input" of my coil but a NC one (inductive sensor). I've come up with this idea : ("Sécurité_1" is ...
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1answer
48 views

Need a modified S-R latch

I have a comparator output who is normally high and goes low from time to time. I need a latch which will change its output from high to low when the comparator's output change to low (and keep it ...
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1answer
47 views

Latching power button with force-off

There's been a lot of soft-latched power switch circuits discussed here and elsewhere on the internet. However, I can't wrap my head around how to implement the following requirements: Battery ...
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2answers
150 views

Dual Coil Latching Relay with LEDs - Opposite LED Triggers on Trailing Edge

This is my first time using dual-coil latching relays (Kemet EC2-5TNU), and I'm running into some strangeness when breadboarding out the below circuit: The coils switch without issue when sending a ...
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2answers
44 views

Latching Switch Pinout

I'm planning on incorporating a latching switch into my design: https://lcsc.com/product-detail/Electrical-Switches_XKB-Enterprise-XKB8080-Z_C318860.html I also found the corresponding datasheet: ...
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0answers
79 views

Latching relays connected in parallel not working as expected

I have a project I'm working on where I need 4 relays to open when power is applied to the board and close when power is lost. I need to use latching relays to conserve power as the device could be ...
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1answer
107 views

How soft latch power switch in this specific circuit is possible?

I am trying to understand the soft power switch operation of a LED lamp I dissembled. The circuit of the lamp is depicted below. The switch S1 can be considered as a momentary on switch (SPST). The ...
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3answers
256 views

Circuit to turn microcontroller on when reed switch state changes (to monitor door lock state)

I'd like to build a circuit that provides power to a microcontroller (ESP8266 in this instance) when a reed switch is changed from closed to open AND when changed from open to closed. This is to be ...
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1answer
217 views

momentary switch latching circuit

I'm very new at all this and hope you will have patients with me, I'm trying to use this circuit diagram to turn a momentary switch into a latching switch, I though it would be straightforward but ...
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1answer
53 views

Voltage reducer on a latching circuit

I have two circuits, a latching circuit and a simple 12 VDC to 5 VDC circuit using a 7805. I would like to combine these two circuits if possible. The voltage source would be a 12 VDC battery. When ...
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2answers
596 views

Is there a circuit simulator out there that has latching relays?

Okay, I'm at my wits end with this one. Having tried a dozen or so free/semi-free circuit simulators, I can't find any that include latching relays. This surprises me as they're one of the most common ...
2
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2answers
117 views

Electrically toggle-able switch?

I'm wondering if a switch exists that fits this functionality I imagine: The user would depress the switch, it would latch and stay depressed. Once the product completes its function, the control ...
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3answers
219 views

MOSFET switching with 5V but latching ON with 12V

I am having an issue with a control signal. I have a CEP50P03 P channel trench MOSFET that is supposed to switch a 12v power supply. I am having an issue I can not figure out. When I power the ...
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1answer
185 views

Transistor latching circuit

I have made the following circuit from a few online sources, it is very basic but uses two NPN transistors to make a latching circuit that toggles when either push button goes to ground. My Falstad ...
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1answer
255 views

making an automotive “dizzy” switch with using a latching relay

My engine builder wants me to be able to turn my car over without it starting to pre-oil the motor due to a remote oil filter. The car needs to be wired so that the coil will not have juice until I ...
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2answers
202 views

What's happening to this 2N3906?

I'm creating a soft-latching circuit for my project, using a 2N3906 PNP transistor and an N-Channel IRLZ44N MOSFET. The circuit is fairly simple; Once switch one is pressed, it brings the gate of the ...
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1answer
95 views

Using two momentary switches to toggle LED

So, this circuit should (in theory, at least) turn the diode on when ON button is pressed, and turn it off when OFF button is pressed. It doesn't though. The diode is powered on at the moment where I ...
2
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1answer
179 views

Can we apply a longer pulse to latching solenoid than its rating?

I've a 6-12V dc latching solenoid, which needs 60ms of pulse to set it to on/off. I'll be using a microcontroller to generate the pulse. I've following questions. What if the generated pulse is ...
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1answer
235 views

Latching switch to single pulse circuit? (monostable multivibrator with 555?)

I am looking at using a latching switch (SPDT) to momentarily connect two pins. This is for a power button for a raspberry pi, so to power the machine from a hold state you have to momentarily short ...
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1answer
499 views

Latching switch, momentary pulse output when switching on

I'm really struggling to find a simple circuit that'll give me a pulse (~1s) when switching the circuit on. The latching switch can't be changed and already controls other circuits, and the new module/...
2
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3answers
255 views

Latch-Up in CMOS-Devices

I recently read something about the latch-up effect in CMOS-Structures but I don't understand why are MOSFETs affected by this effect. I understand that high currents through the source-drain path ...
4
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3answers
1k views

Simple soft power latching circuit for a microcontroller

I'm building a simple device with a microcontroller and I'd like to be able to turn it on and off using the "hold a pushbutton for 2 seconds" trick that is found on so many consumer devices nowadays (...
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1answer
137 views

Turn off circuit using microcontroller signal

I want to turn off this circuit using micro controller signal to base of Q4 transistor. Can I use the same transistor model for Q4 as for Q3? I'm attaching the picture of schematic from Proteus ...
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2answers
1k views

How to wire latching SPDT relay using proximity switches without relay hanging

I have a hydraulic-driven piston pump that I designed and built. I need a way for the pump to automaticlly go up and down. I wired it using a SPDT relay and a 3 wire PNP NC (normally closed) and ...
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1answer
1k views

Latching/Non-Latching Relay Driver Circuit with darlington optocoupler

I'm designing a circuit where an ESP8266 controls two types of relays, a single coil latching relay and a normal non-latching relay. The relays are power relays use to control low power electrical ...
2
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2answers
2k views

latching relay with kill switch

I'm working on a little circuit to place on a vehicle, the expected functionality is to add a kill switch that when pushed it will stop voltage to my load, in the schematic i represent it with a bulb. ...
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3answers
2k views

How does the high inrush relay handle the inrush current?

I was searching through the high power relays(16A, 240AC) and found that some manufacturers have high inrush capability relays and that too upto 100A inrush current. Below are some examples (one is ...
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1answer
117 views

Monoshot false triggering and latchup problem

I use a monoshot to extend the duration of a short duration pulse (few microseonds) to 150 milliseconds. The issue is that the monoshot undergoes false triggering in the absence of valid input: The ...
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4answers
3k views

What capacitor to get for relay coil?

I refer to the diagram from this thread: What is the use of the capacitor in this relay circuit?, which is also shown below. If I were to use a capacitor for my relay coil (12v latching type) which ...
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3answers
436 views

Micropuck LED driver gets really hot

I have a Cree LuxDrive LED powered by a 3.7V 750mAh LiPo Battery hooked up in a circuit with a latching switch. For some reason every time I turned it on, the driver gets really hot and almost starts ...
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2answers
848 views

How do I avoid a race condition in SR latch?

I have designed an SR latch using Cd4001 NOR gate IC. When both S and R are low the circuit refuses to stay in previous state even though I am using appropriate dropping resistors. Is there any way to ...
0
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1answer
102 views

Latching control via active-high battery supply / regulator shutdown pin?

I'm looking to supply an MCU (3.3 V) from battery via voltage regulator: a pushbutton should enable the supply, the MCU then should keep the supply enabled until it wants to shut itself down. But the ...
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2answers
13k views

Single push button relay with reset

I have an automotive application where I would need a 12V relay/circuit that can be toggled with single button between on/off. But it should reset itself back to when input voltage drops to zero. I ...