Questions tagged [switches]

Devices to interrupt or route a signal or power one of several ways.

260 questions with no upvoted or accepted answers
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5
votes
1answer
250 views

Induced power supply noise on switch contact

I have a circuit that has a 24V section and a 5V section, separated by opto-isolators and an isolated DCDC converter. Both sides of the DC-DC have decoupling caps, and the MCU has one per Vcc pin. ...
3
votes
1answer
111 views

Switch between 2 power supply feeds without device losing power

I have done a search on here but didn't find the answer (maybe "woods for the trees") but here goes... A brief 'background' -- In my house, there's a switch by my front door that turns on/off the ...
3
votes
1answer
72 views

Timer activated by Reed on AC solenoid

Let me start by saying thank you for taking the time to read this - I really appreciate it! To the point: I am trying to create a 2-digit timer that resets and then starts at the activation of an ...
3
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0answers
1k views

Tactile switch actuator extension methods?

I am not a 100% sure this is the right place to ask this, but I couldn't figure out another, more appropriate community. I am designing a PCB for a product, which will have a tactile switch. The PCB ...
2
votes
1answer
132 views

Extending PCB switches and LEDs

I have a project where for the prototype, I'm using some off-the-shelf components, namely drone cameras and DVR boards installed in a car. The DVR board has a status LED and a momentary switch which ...
2
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0answers
82 views

Switching speed of MOSFET and BJT

I've read on the internet that MOSFET is faster switching device than bipolar transistor, however, i don't understand why. Considering the fact that transconductance of bjt is grater than ...
2
votes
2answers
53 views

Switches for current source

simulate this circuit – Schematic created using CircuitLab I1 is an wilson modified current source by 4 pnp transistors. SW1 and SW2 are doubts. When SW1 is open, SW2 must be closed and vice ...
2
votes
3answers
162 views

Transistor Voltage Switch - Circuit Help Please

I've been a lurking mechanical engineer for a while, metal fatigue specialty. I could really use some help with a simple circuit design please! I have two pseudo-constant voltage sources that can ...
2
votes
2answers
269 views

Momentary switch for power?

The only switches I have every worked with are basic switches with on/off state, but I want to be able to add a power button to my project that is just like the power button on a cell phone. (hold for ...
2
votes
1answer
196 views

Switch bounce vs LC Spike Voltage

For my EE lab, our professor wants us to show switch bounce, and then eliminate it using hardware, and software debouncing. However, I seem to be stuck on finding the switch bounce in the first ...
2
votes
1answer
51 views

How can I control the route to analyse with HyperLynx in a switch?

Good day to everyone. I recently started using HyperLynx from Mentor and I'm having difficulties in analyzing the signal-integrity of the signals due to having switches in the circuit. When I load ...
2
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0answers
304 views

Control DC circuit with an AC lock switch

I am currently adding circuit with a horn and some lights powered by a motorcycle battery. The circuit should be using about 12v 18A. What I want to do is control the circuit with a lock switch. I've ...
2
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1answer
559 views

Shut down circuit sections

I am currently devising ways to shut off different circuit sections in an embedded circuit. Here is a breakdown of what I am doing and my initial idea. Currently I have a micro controller which is ...
1
vote
1answer
50 views

15 second switching circuit

I am designing a circuit that receives a signal from a motion sensor, and then turns on a light for 15 seconds. I have a rough idea on how to make the circuit, but I am also curious what are the ...
1
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0answers
82 views

What is the Umlaut Symbol in this relay?

I'm wondering if the reoccurring "Umlaut" (Ö) symbol in a manual for a process controller that I'm referencing is an actual electronic representation of something, if so what, or if this process ...
1
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0answers
65 views

PMOS Load Switch Circuit issue

I'm working on a load switch circuit that drives a capacitive load of 1000 uF and a GaN transistor in parallel. The schematic of the circuit is attached. The input voltage is 50 V and the ...
1
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0answers
55 views

How should I modify a welder to add a pedal to enable the output?

I'm restoring/improving an old welder rated 3.2 kW input, 115 A DC output, 52 V no load. I'm adding a ready made soft-start circuit based on a NTC plus bypass relay rated 100 A and capacitors to ...
1
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0answers
43 views

What is the best way to isolate power hold-up circuit?

I an currently designing a hold up circuit for a computer and I need to keep this load isolated from other circuits that don't need to worry about a brief loss of power. The research I've done has ...
1
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0answers
36 views

Can't find replacement for switch

I am trying to repair a nespresso machine(not a job, just for fun) and the PCB had the following switch: I tried to google it as "switch", "switch 4 pin", "1552", but nothing returned a switch ...
1
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0answers
113 views

L298N motor driver not working after connecting SPST switch

So when I had all wired as depicted in the first image, it worked fine, no problems. The red LED on the L298N board was illuminated and the dc motor was following commands from my Raspberry Pi. Now I ...
1
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1answer
40 views

Automatic transfer switch or some such solution

I have only rudimentary knowledge of electronics. I live in South Africa, where we are now experiencing rolling blackouts. (Euphemistically called "Load Shedding" here.) During the day it's just a ...
1
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0answers
68 views

switch without diode

I have a project where I need to put a switch in between the resource from tester and the DUT. My DUT is a 48 pin device (semiconductor IC), each of the pins has its own ESD diode. The switch, for ...
1
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0answers
535 views

Snubber for Relay Contact Switching Resistive Load

I am working on a redesign of some circuit boards and am looking for a way to save space and potentially switch to surface mount parts. Some of the largest through hole parts in use are for an RC ...
1
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2answers
160 views

Quick question. Will this mono/stereo switch system work on my mixer panel?

So basically, I designed a mixer panel for monitoring my band when we play live. However, some of us play with a stereo in ear monitoring system and some of us use a mono speaker by their feet. I don'...
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0answers
31 views

Split Power Plane when using Load Switches?

To do power saving for a battery operated product, I am using couple of load switches to shut down peripheral power when not using that. PCB stackup - Signal(component), Gnd, Power, Signal -- 4 ...
1
vote
1answer
65 views

Using an analog voltmeter to display the changes in out put made by a dimmer switch for a light

I'd like to preface by saying k know little to nothing about electrical engineer but would like help with making a lamp. I want to use a volt meter style gauge to display a different reading for a ...
1
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1answer
295 views

Latching power switch circuit

I am trying to understand: 1) how the following circuit works and more specifically how it turns on. 2) How to to modify it to get a hold on/hold off behavior instead of push on/hold off to prevent ...
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0answers
161 views

How to isolate a RLC circuit with MOSFET switches?

I'd like to isolate, with high-side and low-side switches, a RLC circuit after the inductor has been energized with a current of 2-3A from a 12V source (see sketch). When the RLC circuit is isolated ...
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0answers
34 views

Hook up an automatic transfer switch with two phases only

We have a house in Haiti connected to the shore line. The shore line isn't always working so we bought a generator. I wanted to ground one of the two phases to create one neutral, one phase and a ...
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0answers
55 views

LEDs driven by GameBoy sound

My circuit does not work as I thought it should and I'm really confused now. What I want? Two LEDs which will pulse to audio LEFT and RIGHT channel separately. And same for display BACKLIGHT, but ...
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0answers
65 views

Problem with signal edge in schematics containing high speed IC switch

I am trying to design the following schematics: There are two kOhms resistance which are connected serially. One is load and another is device resistance. I need to apply the voltage in a the ...
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0answers
186 views

What's inside a reed switch that cannot be tested with a multimeter?

I'm shopping for reed contacts that are rated for 230V AC, because I don't want to use an always-on power supply just for a relay and a reed switch. This is surprisingly difficult, but I found this ...
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0answers
76 views

Circuit Design: Momentary switch long press ON, short press OFF

I'm trying to create an accessory controller for my 2001 BMW motorcycle. To those who aren't familiar with the older BMWs, there is a separate "turn signal cancel switch" on the handle bars that when ...
1
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1answer
64 views

Logic circuit shutting off at target voltage

I deleted the old question and posted another one because I felt the question is now substantially different. I have a potentiometer connected to a current source and I want the logic chip to cut off ...
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0answers
54 views

Voltage controlled switch simulation

I'm trying to short two pins on a chip when an audio signal is received and float them otherwise (same effect as a tactile switch). I thought the best way would be to use a voltage peak holder and a ...
1
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1answer
175 views

Arduino and car's 12V switch

I'm trying to control my headlights with my Arduino and a LDR. For this I will use the Arduino as a middle man between the lights switch and the actual lights. The switch has three positions OFF / ...
1
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0answers
219 views

How to get NodeMCU to detect an external switch closure of an unknown voltage?

I'm getting really into home automation as a side project of mine and one of the next things I would love to automate is my doorbell. Short question: If I have a switch (momentary button in the form ...
1
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1answer
207 views

Silicone rubber keypad PCB design

I have a question regarding PCB design and rubber keypad contacts. I did this circuit for prototyping a piano keybed but some contacts seem to be unstable: when pressed it switches from 0 to 1 ...
1
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1answer
78 views

Using capacitive touch switch as guitar pick-up selector

I want to use two Schurter 3-101-401 one for each pick up. I was able to get them wired up but the signal for the pick-ups comes out no matter what. Here is the info https://www.mouser.com/...
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0answers
1k views

How to model MOSFET as a switch on LTSpice

I am trying to use MOSFET as a switch on my circuit. I hope someone can help me model it!
1
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1answer
38 views

Activate motor on speaker sound using speaker wire

I have a mission: I want to put the board of a Google Home Mini inside the Nabaztag Smart Rabbit, an old iot device that doesn't work anymore because they shutdown the server. Nabaztag has two ...
1
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0answers
364 views

Mosfet as a Power Selector Switch - Value of a Resistor & Other Clarifications

I'd like to breadboard a simple circuit which implements a mosfet pair to emulate a mechanical SPDT switch. The circuit schematics can be found here. The circuit looks identical to one that can also ...
1
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0answers
532 views

mosfet n-channel high side switching considerations

I know high side switching is normally done with a pchan mosfet but i don't want have to invert my control signal. So i am curious if i want to source 10mA through the 28V rail on a n channel mosfet ...
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0answers
64 views

Help in identifying two parts

I need to identify two parts that I need to replace, but I'm having a hard time doing it. These are the parts: Part 1: From my research I think it is a trigger switch (http://www.jiaben.com/en/pro....
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0answers
1k views

Replacement for a P-Channel Depletion MOSFET

I've read some of the questions about P-Channel Depletion MOSFETS and I understand their availability is very limited and often expensive. So what I'm hoping to discover with those that view and ...
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0answers
171 views

Proper SPDT switch wiring

Apologies in advance if this has been asked before, but I haven't been able to find anything like it. Please let me know if it has. I'm curious about the proper/standard way to connect a SPDT switch ...
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0answers
133 views

Using NPN transistors as switches for low-current, 3VDC infrared transmitter device

I'm currently trying to hack up an IR remote for electric holiday candles so that I can use Amazon Alexa or Google Home to turn them on or off. To do so, I need to trigger the switches on the hand-...
1
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1answer
487 views

What is the best between a transistor and a pmos and which resistances

I need to create a switch to power on or off a moisture sensor. PIN 10 is HIGH or LOW to trigger either the transistor or the PMOS My sensor consume about 0.6mA Moisture sensor information My ...
1
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1answer
48 views

pushbutton power source to load

I would like to build a control panel to direct K power sources to N loads. A power source can control any number of loads, but a load can only be connected to a single power source. Each power source ...
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0answers
969 views

changeover normally closed to normally open

I have a switch that is used for setting tool lengths on CNC Mill. The switch operates normally closed, and breaks the signal when a tool touches it, which sets the length via a macro. The control ...