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Questions tagged [switches]

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

0
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3answers
171 views

220 VAC/110 VAC to 24 VDC

I'm trying to understand how to build a battery charger. I need to convert from the usually european 220 VAC to 24 VDC but also from USA 110 VAC to 24 VDC like the normal chargers, to adapt it to the ...
0
votes
0answers
18 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 ...
0
votes
1answer
83 views

Using DC generator as power source and switch in multi

I have the following: DC Generator 5V regulator lipo charger (5v input), 3.3v regulator, lipo battery device requiring 3.3v power I only want the battery to be connected to the 3.3 regulator (and ...
0
votes
3answers
327 views

How to Implement Float Switch On/Off LEDs

I've previously built this circuit to control a submersible pump with a PIR sensor: I'm now going to add a float switch to the circuit to prevent the pump running if the water level gets too low. I ...
1
vote
1answer
100 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 ...
2
votes
2answers
193 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 ...
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2answers
66 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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0answers
22 views

12v Bluetooth Module Bypass Circuit Needed [closed]

GOAL: Retain dimming function of 12V Bluetooth LED Dimmer module when not bypassed from its power source. BACKGROUND: LED strip is usually connected to a portable 12V source containing a small ...
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0answers
6 views

Need help wiring low beam and high beam headlights [migrated]

New aftermarket headlights on my daughter's truck have separate lights for low and high beams. I would like to wire them together so the low beam will still work independently, but they both will come ...
4
votes
1answer
99 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" ("...
0
votes
1answer
50 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, ...
0
votes
1answer
102 views

Using a p channel mosfet to switch a RF switch

I'm very new to electronics, i have the following RF switch (CG2179M2) which i need to control using the output signal of my MCU, which will provide a 3.3V HIGH for transmit mode and LOW for ...
0
votes
1answer
93 views

regular wall switch on off led dimmer

Is it possible to make a simple dimmer thats operated just with the flick of the regular wall switch on and off? just like what Philips sceneswitch bulb does? My requirement is 100%, 50% and 10% ...
0
votes
0answers
33 views

Switch to stop connection between usb cable and printer [closed]

This is an electronics question. :-) I have problems scanning documents. To get a scan to work, I have to unplug the usb cable (that goes from desktop to scanner), wait about 10 seconds and then ...
0
votes
4answers
58 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 ...
1
vote
1answer
109 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 ...
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votes
3answers
57 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 ...
0
votes
2answers
98 views

Add tilt switch to this photodiode circuit

I'd like to take this phototransistor switch circuit: And add a tilt-ball or similar switch in series. That switch needs to be heavily debounced, so that it stays "switched" more or less for several ...
3
votes
4answers
222 views

What types of mechanical switches are appropriate for a 200 V DC 20 mA circuit

I have looked at many switches, most recently I considered snap action switches (micro switches). What I prefer to use is a PCB mounted switch, but I cannot find any that can tolerate the V DC ratings ...
0
votes
1answer
107 views

Switch controlled by open/closed circuit

I am looking for a specific product: a type of switch that has an 2-pin remote connector. If these 2 pins are open-circuited, it should produce no (or low) voltage (on different output channel). If ...
5
votes
5answers
8k views

How to inverse behaviour of a switch?

I have a sustain pedal (which is just a momentary switch!) with the wrong polarity (according to the device I'm using it with) : circuit is CLOSED when pedal is pressed circuit is OPEN when pedal is ...
0
votes
1answer
34 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 ...
0
votes
2answers
93 views

Unreliable switch on string of LED lights

I have a string of LED lights (think Xmas tree lights) powered by a wall wart (3.2V 1A) and turned on and off with a simple inline rocker switch I had troubles with the lights flickering and ...
1
vote
0answers
65 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 ...
0
votes
3answers
103 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. ...
1
vote
1answer
106 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 / ...
2
votes
2answers
103 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 ...
0
votes
3answers
55 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 ...
0
votes
4answers
110 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)? ...
0
votes
3answers
51 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
votes
1answer
101 views

Turning switch state at two different voltage

I have a requirement to change the transistor/mosfet switch state at two different voltages. Below is a small graphical representation. 3.3 v (red) to 4.5 (green). switch should be open when the ...
0
votes
1answer
75 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 ...
0
votes
1answer
104 views

Switching voltages with demux and switches

I am trying to design a circuit that, depending on a value that a microcontroller recieves (between 1 and 10), a fixed voltage of 20 V, 40 V, 60 V,... or 200 V (depending on the value recieved by the ...
1
vote
3answers
99 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 ...
0
votes
0answers
33 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 ...
0
votes
3answers
91 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 ...
1
vote
1answer
57 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 ...
0
votes
1answer
115 views

Considerations for debounced power switch with Li-ion battery source

From a battery source, I have connected multiple voltage converters (100V, -1500V etc...). I wish to turn all of this on with a single switch. First of all, will a simple RC filter with large C be ...
0
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0answers
28 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 ...
0
votes
1answer
47 views

Lt-spice switch model

I have a very simple circuit and want to see the current in the inductor. But I do not know why switch is behaving like that... Actually, I supposed to get KA range current. but it gives me very ...
2
votes
1answer
74 views

Charge Injection Confusion

I'm having some trouble understanding the effect that charge injection has on capacitors - more specifically, when there is unequal charge on a capacitor. Consider the following circuit: My ...
0
votes
1answer
35 views

Using P-MOSFET with Gate and Source have same voltage to protect reverse current

I have a question when I am working on MP2639A 2-cell LIPO charger (+8V4) from USB +5V. The recommend schematic uses P-MOSFET to protect reverse current from Load back to a USB plug. taken from ...
0
votes
2answers
122 views

Convert a hall-effect flow meter to operate as on-off switch

I'd like to convert a hall-effect flow meter to operate as on-off switch. the output is in pulses, which arrive at a rate proportional to the flow rate. what I would like to do is have a circuit ...
1
vote
1answer
117 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 ...
1
vote
0answers
42 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 ...
0
votes
0answers
58 views

Any Self-turning switch?

I am looking for a switch, which can turn between 3-4 stages and also do it by itself. Do you guys know what I should search for? Thanks :)
3
votes
2answers
83 views

Electronically triggering contact pad buttons on a wired remote with a Raspberry Pi

I would like to control my AC with a Raspberry Pi. My system is similar to this one, although it is an older model from 2004. Currently the system has a wired controller. There is no bluetooth, wifi, ...
7
votes
6answers
3k views

How can I convert the output from a momentary switch to a pulse on push and a pulse on release?

The title pretty much says it all. I have an idea to try out involving a op-amp differentiator circuit and a diode bridge, but I am flying blind. Also I am trying to accomplish this without a micro-...
2
votes
1answer
44 views

Design ethernet switch for multiple devices on pcb?

I'm working on a pcb design with a Raspberry Pi CM module and a microcontroller with ethernet capacity. The goal is to connect the devices to the internet. I'm currently using a normal ethernet ...
0
votes
0answers
14 views

Non-overridable timed autocut switch

I need a switch which upon a single press turns off for a fixed, constant duration (here 8 hours) and even if the user manually represses the switch during this duration or keeps it overpressed, it ...