Questions tagged [switches]
Devices to interrupt or route a signal or power one of several ways.
2,437
questions
6
votes
2answers
267 views
Button debounce ringing
I have a circuit where I am using a tactile switch to pull 3.3v down to ground and investigating debouncing the button. My relevant part of the circuit is
The 100nF cap does work here my signal has ...
2
votes
3answers
77 views
Help with a PNP Switch
simulate this circuit – Schematic created using CircuitLab
I'm trying to design a simple switch for a electric valve. I'm using a 2N4033, and I'm providing 12.3V between the emitter and the ...
1
vote
0answers
29 views
Looking for I2C audio signal switch [closed]
I'm looking for an I2C controlled device that can select from any one of four or more stereo audio sources. Self learning Raspberry Pi project...
Recommendations? Not wanting to resort to a bank ...
1
vote
1answer
55 views
How else can I design a USB switch?
As a follow-up to my other question: what components I could use instead of a 4PDT switch to create the desired effect of switching a USB device such as a keyboard between two systems? I'm new to ...
2
votes
2answers
82 views
Why doesn't my USB switch toggle between inputs when the LEDs are added?
I'm new to electronics so any helpful advice or resources would be greatly appreciated. I built a USB switch to connect my keyboard to two PCs using a 4PDT switch and it works great. Now I'm trying to ...
0
votes
0answers
24 views
Wifi & 4G lte/3G switch
Has anyone heard of a part or a component design to switch between two networks (WiFi and GSM in our case)?
0
votes
1answer
21 views
Advice for High Side Switch (High Current, Low Voltage)
I'm building a small LED driver microcontroller board and I'm looking for any advice y'all have on switching the power to it up to 9A (would take 3A, if necessary) at 3V - 5V, in a small package. I've ...
0
votes
1answer
36 views
Switching 240V A/C source between two loads with relays
I need to swich a single US 240V (hot-hot-ground) power source between two A/C motors, 20 amps max, with an option of disconnecting both. For this project, design aesthetics is very important and I ...
0
votes
1answer
54 views
Is there a toggle switch that returns to default state on power off?
In my car there is a switch to control traction control that's Normally Closed that I want to swap to Normally Open, however there is a problem. When the car is turned off and back on, the state ...
1
vote
2answers
35 views
Fixing the wiring on a keyboard sustain pedal
I have a cheap keyboard sustain pedal of the basic on/off variety. When the footswitch is pressed down sustain is on, and off when it's released. There is also a polarity switch so that it can be used ...
0
votes
1answer
48 views
Single pole or dual pole relay for switching a 3 kW water heater?
I have bought a WiFi controlled device to control a 3 kW, 240 V water heater (immersion heater) wirelessly but despite being advertised as 15 A, it actually has a 13 A relay which has "push fit" ...
1
vote
2answers
112 views
Need a circuit to detect if something has gone from off-on or on-off
I'm new to circuit design but I'm trying to design a circuit for a power antenna that will send a 5 second pulse whenever it detects a a wire has gone from off-on or on-off.
So far I have designed ...
0
votes
0answers
36 views
What kind of switch would i use to perform the same function twice?
I am looking into building and wiring my own "button box" for a flight simulator and I'm trying to figure out what kind of switch to use for stuff like the landing gear. It uses the same keybind to ...
0
votes
1answer
29 views
1A load with 3 1,5V@2950mAh AA Alcaline batteries
I have a system that is powered with 3 AA Alcaline batteries Varta Industrial Pro (1,5V@2950mAh).
The batteries are connected to a this 3V3 LDO that supplies power to a MCU. I have taken a minimum ...
0
votes
2answers
20 views
Combo Indicator LED / Fuel Pump Relay Kill Switch
I'm looking to wire up simple on/on DPDT switch in my car so that in one position, power is cut to the fuel pump relay and power is sent to a fake alarm LED, and in the other position the fuel relay ...
1
vote
1answer
55 views
BJT NPN Switch not fully turning off under certain conditions
My first post here, I'm relatively new to electronics and this is my first project that I'm trying to accomplish myself.
First off, some background of what I'm trying to accomplish. I am trying to ...
1
vote
2answers
63 views
Disconnecting a resistor out of parallel with a switch
I'm modifying an existing circuit. In order to perform this modification, I need to tap a resistor in the circuit and put another in parallel. By connecting this resistor in parallel (changing the ...
1
vote
1answer
30 views
I have a simple circuit with a relay with a SSR. I am getting leakage measured using a multimeter of ~4v. Is there a way to eliminate the leak?
I have a simple circuit. My computer controls an SSR via a 3v dc signal. The load is from a VAC transformer transmitting 10v ac. When "off" I am measuring ~3v coming from the SSR using a multimeter. I ...
0
votes
1answer
27 views
Modify LED circuit with a MOSFET
I have this existing LED circuit with 2 LED strips with built in resisitors and 1 switch. Normally 1 LED strip is always on and when the switch is closed the other LED strip also turns on. Power ...
0
votes
0answers
19 views
Detect multiple reed switches in series individually
I have a device, which has a safety relay, where the relay coil is connected to +12V over 2 reed switches.
Now I want to detect, which of the reed switches is not closed, with a microcontroller, but I ...
1
vote
1answer
45 views
Switch power on/off when SD card is inserted/removed in slot
I have ESP32 and I'm using it to read/write data from an SD card that is directly connected over SPI. This works fine. Now I want to switch on the ESP32 automatically by switching on the 3.3v power ...
0
votes
3answers
67 views
How to automatically disconnect from battery when USB +5v is present
I'm creating a SMD PCB where space is extremely limited.
Usually, the application is powered by a battery (Single cell 3.7v lipo).
To charge the battery, I'm using a USB cable.
What I'd like is for ...
0
votes
0answers
43 views
How do I work out the correct PWM frequency for my application (motor)? [duplicate]
I am working on a project and want to drive a motor with a 12V PWM signal (Motor connected to 12V and the Motor- net on the diagram).
I have it working, however i'm not sure how to work out the ...
0
votes
1answer
59 views
How is a PMOS transistor used as a switch?
I am trying to understand switching behaviour of PMOS transistor and how exactly it passes a bad 0 value. I'm getting confused with the notation.
More specifically, when the PMOS is on and $$V_(in)=...
0
votes
3answers
88 views
How to safely expose one wire of an AC mains circuit?
I need to use a rail to connect one moving piece where a switch is, to a fixed piece where a power tool is. The rail is exposed, so I need this connection to be safe, like 12V or below. I'm guessing I ...
0
votes
1answer
48 views
Why is the switch drawn like this (NRST, STM32)? [duplicate]
The below part of a circuit is from the AN2586 Reference design for an STM32F1:
https://www.st.com/resource/en/application_note/cd00164185-getting-started-with-stm32f10xxx-hardware-development-...
0
votes
1answer
48 views
A regular on / off switch AND a momentary one
I'm building a drill press and I'd like to be able to turn it on with a momentary switch on the handle, but sometimes I need both my hands free while it's running. Ideally, I'd use a "lockable" ...
0
votes
1answer
47 views
Using a 30V Switch on a 28V load
For a project I'm working on, I wanted to use a LED Switch for a 28V load, and the switch itself is rated for 30V, 10A. Even though the switch is within spec, is it good practice to use a switch rated ...
0
votes
2answers
38 views
Using a single pushbutton switch for 2 seperate circuits
I'm trying to rediscover my technical roots and am in need of some knowledge from experienced hands.
I have two toy sirens for my nephews pedal-cart, but I need them to both sound when a single push ...
0
votes
3answers
77 views
How to detect 3 way slide switch positions?
With one of this 3 position 8 pin slide switches, I want to detect all three positions:
Required function:
Position 1: Node1 to ground
Position 2: None
Position 3: Node2 to ground
If I pull an ...
0
votes
3answers
36 views
Fast switching of a 24V valve
I'm trying to make a circuit using tc4427 and some other components to make a fast switch for a 24V valve using a signal from a microprocessor. I've modeled the signal from the processor as a pulse of ...
1
vote
1answer
52 views
Which type of transistor (MOSFET or BJT) would be better to use for the longest battery life?
Background
These two circuits will function as a broken loop warning device. Can think of this as a circuit that sets off an alarm when a loop of wire is cut. This cut wire could also represent a ...
1
vote
3answers
54 views
How do I speed up transistor switching in low side power switch?
I am working on a project and want to drive a motor with a 12V PWM signal (Motor connected to 12V and the Motor- net on the diagram).
The circuit below is an idea I have, however after I built it, it ...
0
votes
1answer
28 views
Trigger two circuits with single SPST switch
I'm an electronics noob willing to learn. So I have a door bell that looks like it is wired like this:
And I've bought a fancy 3V battery powered device that is intended to be wired simply like this:...
-1
votes
1answer
93 views
a circuit that gives momentarily contact when I close a switch
I need a circuit that gives momentarily contact when I close a switch and will give another momentarily contact when I open the same switch again.So when I switch a switch on there must be a circuit ...
0
votes
1answer
26 views
How to control a capacitance control panel from a Raspberry Pi
I have a touch control panel with only one lead going to each "button" on the glass, it is not a full circuit only half of one.
I have concluded if i ground one of the pins (ex: power), it senses and ...
1
vote
1answer
39 views
HV capacitor switch
I have in hand a 220V:600V isolated transformer and a HV bridge rectifier and I'd like to charge a 250uF capacitor with adjustable voltage from 200V to 500V. My idea is to use a switch between the ...
0
votes
1answer
31 views
Band Switching Circuit
I am building an oscillator circuit at 4-6 GHz and I am trying to make a band switching circuit to add capacitors up to 10pF. Every band switching diode and low capacitance transistor I have tried ...
2
votes
1answer
59 views
Motorized rotary switch
Motorized potentiometers are easy to find and often used e.g. in music studio equipment, but I could need a similarly motorized rotary switch for a project. I am either searching for the wrong term (...
0
votes
1answer
36 views
Help Troubleshooting Relay for Vehicle Offroad Lights
I am wiring up 2x 55W Halogen lights and 2x 100W Halogen lights on my '01 Subaru Outback. I want all 4 lights to come on when I turn the switch on. I created the wiring diagram which I followed during ...
1
vote
1answer
44 views
finding the current in a branch with resistor, capactor and a voltage source
I'm solving a question in Linear circuit analysis 2 class. the question is to analyze a switching circuit with inductors and capacitors. this is the circuit in the time interval drawn in S-domain ...
0
votes
4answers
125 views
What is failed closed switch?
What is the meaning of switch failed open or failed closed in electronics?
I did a search but without results.
0
votes
2answers
42 views
Adapter load switch MOSFET schematic questions
I have a few questions concerning a input adapter load switch schematic for a battery charger IC (bq25780S). I posted a screeshot of this part of the schematic from the reference design (BQ24780S ...
0
votes
1answer
31 views
Question Concerning a Lamp Switch
I have a question regarding an overheating lamp switch I just fixed in my living room. Below is a diagram of what it looked like internally. It's not exactly a push switch, but a rotating wheel which ...
0
votes
1answer
61 views
Designing a USB Selector Switch for a Printer and 2 PCs
I would like to build a circuit that allows me to use a single printer with both of my PCs. It is exactly something like this:
Also, I would like to use this type of switch:
in order to select ...
1
vote
4answers
79 views
Is it practical to make home-made membrane switches in low quantities?
I'd like to custom-make membrane keyboard switches as a replacement for the cheap push buttons I am currently using. You have all seen these kinds of buttons. If you have experience making these ...
1
vote
1answer
65 views
How can I replacing broken DPDT switch with direct wiring?
The "gearbox" of my kids car i broken. It's the kind you sit in (at least the kid) and pushes a button with the foot and the car goes forward or backwards, depending of the state of the "gear". From ...
0
votes
2answers
37 views
A very basic question about PLC field input switches
Below shows two simple ladder logic examples written for a PLC:
As far as I understand, the -| |- and -|/|- above are the symbols we write for the PLC not the actual input switches.
But we also need ...
0
votes
3answers
69 views
How to add an emergency stop switch in a circuit?
I am into a project, where I have made a a bot, which has a 6 degree of freedom robotic arm with four wheels. I need to add a kill switch that is connected to a relay, which stops all the 10 motors. I ...
0
votes
2answers
36 views
RL circuit with switch
I'm stuck on this problem I'm working on:
With the following questions:
So my approach:
Well to start with there is two cases: t<0 and t>0, so I thought that I would start to find IL(0), the ...
