Questions tagged [switches]

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

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858 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 ...
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25 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 ...
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34 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 ...
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44 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 ...
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66 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 ...
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119 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 ...
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24 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 ...
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39 views

The best type of electronic switch to control the signal coming from a pickup coil on a motorcycle

So, my motorcycle has an ignition system that's not really secure, all someone has to do is pull the ground wire going to the ignition coil and anyone can start it up. The only other way to stop it is ...
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118 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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24 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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54 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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62 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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156 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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59 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 ...
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42 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 ...
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150 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 ...
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969 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!
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265 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 ...
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395 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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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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846 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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143 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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121 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-...
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793 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 ...
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124 views

Analogue multiplexer using JFET for small signals

I'm working on a circuit with a non-inverting amp and I would like to switch between two reference voltages, both with low output impedance. So in effect i want something like this: simulate this ...
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129 views

Using a MCP23017 for detecting open door/window

I'm not a hardware guy. My plan is to read input states using an MCP23017 connected to a Raspberry PI. My doubt is about the switching circuit. My plan is to use Ethernet cable pairs to wire the ...
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98 views

Automatically connecting LiPo batteries in series (for charging)

I have a battery charger capable of balance charging up to 10 cells in series (10S), but most of the batteries I use are somewhere between 1 and 4 cells. I have plenty of experience charging the ...
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254 views

Switch CB Radio mic with SPST button

I'm a beginner with this type of electronics, but want to try this. I have a CB radio with a 6-pin mic/controller. The pinout looks like this: There is a DPDT switch in the mic that switches ...
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79 views

Current across high speed mechanical switch contact even if it can’t be measured?

If I am cycling a mechanical switch at a frequency higher than the bandwidth of a current amplifier and biased using a DC source, is current actually flowing across the contact? The following ...
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115 views

test 0.5A inductive load through switch circuit

We are a switch component manufacturer and typically run life cycle tests with resistive loads through our switch circuits. Can someone recommend a circuit diagram set up to test an inductive load ...
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91 views

FET Default on, Turn off with Optocoupler

I am relatively new to electronics and having trouble designing a circuit for a redundant power supply, which I would like to switch to battery if the voltage regulator turns off. This will be ...
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158 views

Latching and Momentary Combo Switch

I am looking to recreate a switch circuit I have seen on an intercom system. The switch allowed for two functions, while using one momentary switch. When the switch was pressed and emetily released, ...
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77 views

P-Ch high side switch output drop?

I am making a cutoff switch for a SLA battery using the this circuit V2 is the SLA battery, V5 is 0V or 5V coming from a some other logic circuitry. The simulation comes out fine. I understand that ...
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97 views

momentary push switch triggering twice

I have a momentary push switch connected to my mbed microcontroller. The switch is used to trigger an interrupt which changes a setting on the device. At the moment the button works around 70% of ...
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118 views

Optimal power supply for RF switch

I am planning to use an RF switch to pulse a signal >1GHz. Specifically, I'm interested in the ZASWA-2-50DR switch from Minicircuits (http://194.75.38.69/pdfs/ZASWA-2-50DR+.pdf) due to the low rise ...
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190 views

Modifying a N64 controller to connect to a switch

I am trying to make a game, and I need to turn my N64 controller on and off from a micro controller (STM32F4). My microcontroller has an output pin that outputs approximately 5V, for testing reasons I ...
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282 views

Low-noise SPDT switch

I need to produce an extremely low noise SPDT switch. This switch will take two different inputs to a single 16 bit ADC. The inputs are 50 ohm BNC outputs from trans-impedance amplifiers. The ...
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1k views

Convert a NO push button into an On/Off button

I'm building a boombox, and it needs a couple of switches for main on/off, voltmeter on/off and LED lights on/off. Since I don't have any metalworking tools I am going to buy a premade front panel, ...
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113 views

MOSFET Behavior During Pulsed Operation

I am trying to use back-to-back MOSFETs/IGBTs to isolate my pulsed supply from my load. In theory, I will switch on the MOSFETs, and the pulsed supply will be attached directly to the load (but not on ...
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132 views

Switching cold cathode fluorescent lights on and off without relay?

I have a few sets of 2-in-1 CCFLs that are designed to be powered off the 12V rail of a computer PSU. I'm planning to build a large 7-seg display using them so I'd like to be able to switch them on ...
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203 views

How can I trigger an LED with ultrasound

CASE: I would like to trigger a few independent LED's wireless-ly as cheap as physically possible. It is simply a LED connected to a battery. (The LED-part must be cheap, the transmitter does not ...
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295 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 ...
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41 views

Improving effciency in medical implant with load switching

I'm trying to design and simulate the Q-modulation technique for a body implant. The technique involves two loops: one outside the body, with resonating LC tank producing a big voltage. Another loop ...
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29 views

Protecting back to back mosfets

I'm designing a high side back to back common source bidirectinal power switch made from n-mosfets. schema: Schematic attached. The questions: How can i protect driver from voltage spike from ...
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51 views

Switch DC/DC Converter through Fiber Optic Signal

I need to send a signal through fiber optic to switch a DC/DC Converter (I want it to be on when there is photocurrent, and off when there isn't), I can't use a normal cable because I want to do that ...
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20 views

Issues due to sudden load disconnection/connection

I am working on a circuit (schematic enclosed) which is being powered by a high discharge LiSOCl2 battery. A TPS61232 based 5V booster powers two loads: LOAD1 is directly connected to the 5V bus ...
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42 views

Can you identify this type of switch? Need to replace it

This is hopefully just a simple one to fill in my inexperience. I have a busted rotary switch that I'm trying to replace and I feel like I cannot find one for the life of me, can you tell me what this ...
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18 views

Profet Smart Highside Power Switch Output Always 'High'

I bought the Infineon Smart Highside Power Switch - PROFET BTS442E2, in order to switch a ~16V supply using a logic level PIR sensor. BTS442E2: http://www.mouser.com/ds/2/196/Infineon-BTS442E2-DS-...
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37 views

How to create switch that changes from HIGH to LOW states when receiving a HIGH signal?

I’m creating a circuit and one of the controls is a tactile SPST switch where the common is connected to VDD. What I’m trying to do is to have some SPDT where its common is connected to a multiplexer’...
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52 views

Raspberry Pi GPIO output not working with MOSFET N Channel Switch

My circuit is below - I'm trying to switch a solenoid valve using a Raspberry Pi. I have tested the MOSFET switch with the dedicated 3v3 pin on the Raspberry Pi, and have also tested that GPIO pin ...