Questions tagged [switches]

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

416 questions with no upvoted or accepted answers
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1answer
219 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 ...
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0answers
37 views

frequency of MCP3008

I built BOOST CONVERTER, I sample the output voltage with A/D and control it using RASPBERRY Pi3, I set the switching frequency of the BOOST CONVERTER 70KHz, and the frequency of the MCP3008 1.35MHz, ...
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0answers
48 views

Automatic switches for a 12 V LED with two separate power sources

I am converting a Mercedes Benz Sprinter van into an RV. I have a 12 V LED dome light (actually several) that activate when a door is opened, powered by the vehicle's power system (battery/alternator) ...
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0answers
74 views

What complications arise when designing a USB device sharing switch?

I wish to design and build a USB switch capable of transferring one USB keyboard between one of two computers. I wish to automate the process of unplugging the device from host A and plugging it ...
3
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1answer
144 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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1answer
293 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 ...
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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
61 views

Problem Implementing high side P channel mosfet power source selector

I have build the above circuit on a breadboard and it is almost working but not quite. I've spent a number of hours on the problem to no avail. My background is not electrical but I've been building ...
2
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3answers
103 views

Switch design for shorting the power control pins?

I have been struggling to design this switch for a while and I would appreciate any help. Problem Background: I'm designing a power system for a submersible, using the Mini-box OpenUPS battery ...
2
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1answer
74 views

How to choose MOSFETS by using the datasheets infos?

I know all the theory behind the MOSFETs, how to calculate the Id current based on (W/L) and (Vgs-Vth) and etc. But, now that I need to project a real solution, I feel like all of this is kinda ...
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2answers
185 views

What is the correct name of this type of switch

new here so be kind. What or how do I make a toggle switch stay on as long as current is flowing through it and toggle to off once it stops. I did try all sorts of naming searches in google but came ...
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0answers
84 views

Add LED Indictor lights to 3 or 4 way battery selector switch

Situation: Two battery banks in a solar setup (12VDC). A main DC set of circuits (lights, pump etc) can be powered by either of the banks through a three way selector switch (Bar1, Bat2 or Off - high ...
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0answers
82 views

Controlling 120v line with a 12v switch on a different line

I have 10a 120v power sockets in my garage that currently doesn't have any switch on it and powers some overhead lights that I have plugged in. Separate to that, I have a 12v circuit powering various ...
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0answers
232 views

pass-through Thunderbolt KVM Switch

I can not find a true pass-through KVM Switch for USB-C (Thunderbolt) to buy. So I am thinking about maybe building one myself. Currently I am just plugging and unplugging the Thunderbolt (USB-C) ...
2
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1answer
266 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 ...
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0answers
373 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
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2answers
63 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
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1answer
67 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 ...
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0answers
306 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
601 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 ...
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1answer
51 views

Terminology for components found in Kitchen Timer

Apologies if this is a duplicate, by definition I'm not sure what to search for. I took apart a kitchen timer and found a few things I'd like to learn about, but couldn't find the right terminology to ...
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2answers
53 views

Current Dependent Switch

I have a 24v DC circuit; I need a contact that breaks the positive line if the current in the negative line differs from the current in the positive line. So if the negative line has become broken or ...
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0answers
41 views

DC step-up converter, slecting 2 different Vout with SPDT switch

I want to modify a DC-DC step-up converter that uses a single potentiometer that sets the voltage to use a single SPDT switch where I can select the output voltage during operation without turning the ...
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1answer
43 views

Touch switch for hanging lamp (touching metal bar): Ideas?

A few years ago, we have bought an IKEA Glimt hanging lamp that operates with halogen lamps. It has a "touch dim" functionality, so when a person touches the metal bar of the lamp, it dims (...
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0answers
39 views

Switch off device when battery is charging

I need to disconnect the rest of the circuit when battery is charging for safety reasons. I use a LiPo battery which it's charged with an IC that is powered by 5V DC thought a micro USB connector. ...
1
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1answer
96 views

Kill Switch For Car to Deter Theft

I am in the process of making a kill switch for my car and after doing some research I couldn't find the answers that I needed to start the project. One of the biggest questions I have is how can I ...
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0answers
51 views

How to drive a battery-powered heating element with temperature feedback control

Preface (not necessary to answer question) I am not an electrical engineering student, so I am very far out of my element. However, I do have to complete this part of the project and am having a lot ...
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1answer
62 views

Can I control the flow of a 12V power supply with a 4.5 volt power supply and a IRF3205 mosfet?

To start I am very much a beginner at electronics and am very limited in my tools. I bought a IRF3205 mosfet a few days ago hoping that I could use it in a circuit I have where a 12V power supply at 1....
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0answers
52 views

Low side MOSFET switch disconnecting charging

I have a problem with the design of low side MOSFET switch, that would be implemented in my electrical system to disconnect PV panels from a battery. This switch would be controlled by Controlling PCB....
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1answer
81 views

Switch 12v solenoid from 3v3 control signal

I am going in circles on the web and appreciate your help with this novice question, operate a solenoid with a mosfet (original idea, I know). I bought a Gravity DFR0457 to switch a 12V solenoid on ...
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2answers
54 views

Help with P channel FET not turning off

The circuit consists of an NRF52840 MCU controlling the power to a CO2 sensor. The output from the sensor goes to a buffer which then feeds it back to an analog input. The MCU operates at 3.3V while ...
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1answer
64 views

Logic Converter driving logic level Mosfet Gate

I am wondering if anyone can comment on the feasibility of this circuit. My ultimate goal is to switch a 12V solenoid on and off using a 3.3V microcontroller, but I have had trouble so far. I want to ...
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0answers
14 views

How to wire an outside switch with separate load compression glands

I have a remote control outside switch (Knightsbridge IP663G) which splits a mains line into three, its taking a uk mains cable through the left and I want to connect another mains cable (for lights ...
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0answers
56 views

MOSFET drain current during turn ON time

In the below picture, once the Vgs is greater than Vth, the current Id starts to increase linearly. But at the same time, Vds is higher and hence the MOSFET is in saturation region. In saturation ...
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0answers
32 views

How to connect a ENC28J60 or ENC424J600 to a KSZ8091 PHY and from PHY to an unmanged strapped configuration to a KSZ8863 or other switch

How would one go about connecting MAC chip to a PHY and then to a switch for dual ports for daisy chaining? Rather be a strapped configuration for use in unmanaged mode so no need for MCU software ...
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0answers
11 views

How to connect switches to PWB on IP69K sealed pannel without wiring harnesses while still allowing easy separation of board and panel?

I am working on a project that has a panel that has several push-buttons, and rocker-switches on it. The buttons/switches connect to a PWB that sits behind the panel. The buttons/switches/panel need ...
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0answers
45 views

Using Parallel MOSFETs as a simultaneous switch

I have searched quite a while, but using parallel MOSFETs to alleviate thermal issues and dividing currents seemed to be the critical issues for lots of people. For me, I'm trying to use the parallel ...
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0answers
29 views

400a Brushed DC Motor Switching Device

So I'm building what you might call an intentionally janky electric vehicle, and need some advice. In case anyone is wondering, the vehicle in question is a Ripstik - I currently have four of these ...
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1answer
78 views

5v analog switch for 3.3v logic ok?

I have a project where I want to interface with a keyboard matrix / scanner (this is a PCB from a consumer electronics device). There's already an implementation that uses some analog muxes for this, ...
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2answers
143 views

High side P-channel mosfet switch for BLDC driver (42V ~13A at peak)

I'm trying to design high-side switch for BLDC motor controller(42V ~13A). I understand that low-side switch is more efficient in this case, but controller schematics(bought as is) has an issue. It ...
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1answer
97 views

CD4043 latch breadboard VS PCB

I am working on a circuit that contains CD4043 R/S latch. The design on the breadboard works and everything is great, as soon as the PCB was manufactured and components were soldered, an issue with ...
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1answer
36 views

Wiring a switch to a new power supply for a 12v lamp

I am trying to fix a sign that wouldn't light up anymore and I got confused when it came to installing the actual switch. It does work now but with the "fix" (replaced electronics of the ...
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1answer
56 views

Voltage divider on optocoupler emitter output

I am trying to control a load switch from the GPIO pins of an STM32 which outputs 3.3V. They need to be isolated using the optocoupler shown. The problem is that the isolated voltage supplied is 24V, ...
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0answers
46 views

How i can automate a circuit using transistors instead switches?

I'm recycling the counter circuit of a microwave, for use it as a stopwatch, that turns on automatically, and start the count per seconds immediately when turns on, the circuit have two buttons "...
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0answers
18 views

Continuous duty tolerance for automotive resistors

What is the designation for resistors to be used in 12 v automotive applications? The resistor would pass 5-10 V continuous while the vehicle is switched on. The goal is to lower the standardized ...
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0answers
29 views

Delayed Switching Between USB Peripherals

I have two USB sensor pads that cannot be connected simultaneously to the computer. Currently I am using a USB hub with individual on/off switches for each port. To change pads the user MUST turn off ...
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1answer
78 views

What device controls whether a signal is high or low

In circuitry, there is always inputs in circuits (for example: input A and B into an AND gate), but what exactly allows these inputs to switch states? I think the best way to illustrate what I have in ...
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0answers
22 views

Timer not having output after initial powering

DGM TIMER RELAY BOARD 12V 1S-1HR Time Delay ON or OFF 12V Relay Board with jumper settings and 8 Time Ranges selectable from 0.1s up to 1 hour accessing loads 250VAC 10A or 30VDC 10A I believed this ...
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2answers
70 views

BCW71 NPN transistor as a switch

I have a simple circuit using an NPN as a switch using the BCW71 (https://www.mouser.es/datasheet/2/308/BCW71-D-1802620.pdf), as seen in the following picture: My issue is that when I put 3V3 at the ...
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0answers
43 views

Transistor as Momentary Switch Wemos D1 Mini Reset

I am trying to create a water alarm based on the Wemos D1 Mini and an off the shelf water alarm. The basic premise I am trying to accomplish is when the sensor creates a circuit this then causes the ...

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