Questions tagged [switches]

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

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1answer
60 views

How does voltage/current limits work in switches?

I want to get a rotary switch, it says that it can handle 600 V and 40 A. I will use it to turn ON two DC brushed motors of 12 V 20 A. So, the voltage is way too high but the current is just right. ...
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1answer
26 views

touch switch time problem

I was looking for a way to make a touch touch switch and i found this circuit on the internet but the problem is , it goes off automatically after few seconds is there any way that i can control it ...
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2answers
56 views

Using transistor as switch in the “middle” of the circuit

I have an rather complex circuit with button micro-switch in the middle (actually, it's RF remote control with 3 buttons). I would like to be able to simulate the micro-switch click on it with one of ...
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1answer
53 views

Pre charge resistor switch

I have a 12V 40A motor. I have a switch between the motor controller and the battery. I want to put a pre charge resistor in the path. Like in the figure. My questions are: 1) The pre charge ...
3
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1answer
80 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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2answers
98 views

How to make momentary connection on power on?

I have a mini-computer Beelink AP34 with momentary power button and I need to simulate short pressing of this button once it is connected to the power (12V DC). The reason is that it doesn't start ...
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2answers
39 views

Triac switch cause of heating

As a newbie to hardware design, I'm having some trouble picking components. I want to switch a 24V AC Solenoid valve using a triac. According to my research/experience, transistors heat up during use. ...
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0answers
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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1answer
45 views

Design of a motor SPDT switch that can be triggered by 5 V or 3.3 V digital output

Problem: I am designing the electrical system for a vehicle that has 12 brushed dc motors / linear actuators, they are driven by 6 identical dual-channel motor driver boards, that provide a maximum ...
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1answer
41 views

Reverse function optocoupler in series with physical NC switch?

I've read this answer (reverse function optocoupler) but my case is different: I've got a CNC mini lathe. I have a limit switch on one of the lathe's axis ends (X+) wired as NC to my Gecko G540 ...
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3answers
90 views

Why Does this Short? [closed]

simulate this circuit – Schematic created using CircuitLab I'm new to electronics and wired a dc motor to a battery and switch. After the battery got really hot, I realized that it was probably ...
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0answers
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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1answer
61 views

NPN transistor won't saturate when Vcc is greater than 7 volts

Am I missing something here? I have an NPN transistor (2N2222) with a 10K resistor from collector to Vcc. Also a 10K resistor from base to input signal. Emitter is grounded. The base input is ...
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1answer
47 views

Relay or Transistor as low DC switch

I am working on a project for a watering controller where I would need to turn on or off an solenoid valve (electric valve), my first thought would be to use a relay, but I know relays are good for ...
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1answer
39 views

How to bypass minimal load limitation on a power switch?

I got a power switch which seems to have minimal load that makes it incompatible with LED lights. Schneider GUPA1411BSS 1 Gang 1 Way PIR Switch — after unpacking I found it has only L, L1 and earth ...
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2answers
77 views

Need to turn on a relay for half a second when constant power is applied with a switch

I'm looking for what circuit I'd need using basic components to do this task. Essentially I have a switch that turns on two relays, one of which needs to be on as long as the switch is depressed, but ...
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5answers
5k views

Why can't I see bouncing of a switch on an oscilloscope?

I'm trying to view the bouncing of a simple switch on an oscilloscope. I have prepared a simple breadboard circuit (power → switch → resistor → ground). The problem is, it is displayed as a perfect ...
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1answer
60 views

buck converter with a simple bypass schematic mode?

in my design i need to place a buck converter 10-30V input with a fixed 12V output. my concern is that when the battery volatge level is low (for instance 10v) the device will stop bucking. so i want ...
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1answer
49 views

BJT switches pair

simulate this circuit – Schematic created using CircuitLab I'm trying to do something like this: V1 is a variable (0 to 3.3V) voltage source, so above some value like 0.7 ~ 1.0 V I want Q1 as a ...
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1answer
80 views

Switching circuit

I am making a switching circuit with two input sources A and B of 5 volts each and one or more outputs C1, C2, C3 etc. Source A is constant and source B is variable, has two states on and of. Source B ...
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3answers
51 views

How to debounce a low pulse switch for automotive lighting

Hoping you guys can give me a hand with some wiring that I can't quite figure out! Background: I'm trying to rewire a set of automotive lights - these are normally controlled by a computer but I'm ...
2
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2answers
49 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 ...
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1answer
175 views

“Normally closed” switch with NPN transistors

Is it possible to have "Normally closed" switch with NPN transistor when the voltage at the base is 0V? So far I only managed to achieve this result with NPN transistor when the base is HIGH. When the ...
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0answers
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 ...
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2answers
57 views

what is the right power supply switch for a sensor?

i'm trying to control my sensors power supply to reduce the current consumption of my project. i'm using ATmega328p that collect information from different sensors (digital and analog sensor) and send ...
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3answers
65 views

High side Mosfet switch leakage issue?

Wasn't sure how to headline this but here it is: I'm debugging one of my coin cell ON/OFF switch. Circuit is as follows: simulate this circuit – Schematic created using CircuitLab Basically a ...
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votes
1answer
59 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 ...
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0answers
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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2answers
33 views

Two 12v 1A DC power sources using a 1 gang switch?

I'm wondering if it is possible to connect two 12v 1A DC power sources to a single switch? And if so, how would such a schematic look like. The two power sources will then power their own things.
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2answers
142 views

dpdt switch to spst switch

I am trying to build a raspberry pi gameboy emulator with a custom board inside of a gameboy adv sp shell. I decided to use an open-source board made by some guy on the internet and I will be ...
1
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1answer
37 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 ...
0
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1answer
73 views

Switch for low voltage, high current Shape Memory wire

I need a switch to allow current to pass through a wire to Joule heat it. This is a nickel-titanium wire (Shape Memory Alloy, SMA) which has been programmed to bend into a particular shape when heated....
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1answer
82 views

Single key not working on DIY mechanical keyboard (xd75re PCB and Switch both work)

I have assembled my first mechanical keyboard using the xd75re PCB. I used a plate mount, and all of the switches were installed without issue (this PCB has hotswap). When I used keyboardtester.com to ...
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2answers
70 views

What type of switch is this push switch [photos]?

I suspect this switch isn’t functioning correctly and would like to replace it but can’t find one similar. What sort of switch is it? The front is a push with two states (in/out) and has a bulb to ...
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1answer
51 views

Smart Wi-Fi Switch with No Ground

I want to install some smart switches in an older home without ground wires. I'd also prefer not having to purchase a "Smart Hub" as they seem to be going away and not necessary. Note, I use Google, ...
4
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1answer
112 views

How do I assemble the mechanical parts of panel mount switch? (lock ring, lock washer, nut, etc)

I'm sure this is a very simple question, but I'm not familiar with the different mechanical parts of a simple switch. For example, I've purchased this switch and it includes: Switch "Lockwasher" ("...
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4answers
74 views

4.5 V on gate of Mosfet while switch open

I have a strange behavior with the circuit below. (the bidirectional logica level should be read as: VL = Voltage Low GNDL = GND Low VH = Voltage High GNDH = GND High L1 = Low channel 1 (I did only ...
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3answers
64 views

Help with making sure a correct use of a BJT

I'm designing a PCB that receives 3 power inputs 3.3v, 5v and 12v. I need simple way to switch all of them of in one go. Here is a schematic of my PCB My 12V line is for running a ws2815 led strip ...
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1answer
95 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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0answers
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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3answers
122 views

Why is my crystal oscillator not working with KSZ8999 switch?

I am using KSZ8999 ethernet switch from Micrel and I have problem with 25 MHz external oscillator. There is constant 2,1 VDC on output pin which is VDD for the switch, so crystal is not oscillating. ...
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3answers
83 views

Question regarding ground when using teensy to control a mosfet switch

Despite the fact that I'm pretty new to electronics I'm working on a quite ambitious project which is basically a USB-Midi Controller attached to different devices that send different signals. The ...
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4answers
135 views

Can an optocoupler be used as a switch [closed]

I am trying to replace a analog switch (the switch is a momentary button in a low current DC situation) with optocoupler. Is it possible to use an optocoupler as a switch (i.e. just on/off)? ...
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3answers
88 views

AC rocker switch on a DC circuit

I ordered a set of DC rocker switches that were advertised as "4A 12V DC SPST" I was planning on using one to power an Arduino based project using 5V DC which will draw no more than 1 to 2 amps. ...
0
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1answer
76 views

how to switch off multiple power source (+5/+12/3.3) in the same pcb

I'm designing a PCB that receives 3 power inputs 3.3v, 5v and 12v. I need simple way to switch all of them of in one go. Here is a schematic of my PCB I looked into using a relay but all the types I ...
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0answers
37 views

SMD Detector Microswitch Replacement

One of my son's toys stopped working and I decided to jump in to see what was causing the problem. I found that a number of the smaller detector microswitches had their tabs broken off. Therefore ...
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1answer
63 views

Override One Lamp in a Four-Lamp Circuit Using Transistor?

simulate this circuit – Schematic created using CircuitLab I have a circuit of 4 light bulbs, with single switch on the positive terminal that will turn all the 4 bulbs at once. EDIT: Light ...
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3answers
166 views

Can I use a 12v 20A DC switch for a 24v 10A DC load? [duplicate]

simulate this circuit – Schematic created using CircuitLab I have a toggle switch that is rated for 12v 20A (240 Watts) and I have a load from a battery that I want to turn on or off with this ...
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0answers
36 views

Slope of the Inductor current

this forum is very helpful in the term of power-electronics. I got a question about LT-spice simulation. I want to compare the slope of the inductor current in two circuits.The only difference between ...
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3answers
122 views

How to remove leakage current from nRES transistor switch?

I have this AVR reset pin design, which provide a 12V into the nRESET pin of an ATtiny μC. It's function can be describes as follows. (a) An input signal given by a "low" (0) on ...