Questions tagged [switches]

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

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27 views

Frequency Sensitive Switch

A legacy product we are making uses this obsolete Frequency Sensitive Switch, Consumer Micro FX-301L. The switch is setup such that it switches on (-12V) at 2000Hz +-100Hz and switches off at 250Hz. ...
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3answers
52 views

Problem with a relay decoupling voltage

I made a simple circuit to alternate its output between two inputs: a photovoltaic panel and a 12V DC voltage source. The schematic: The step source represents the photovoltaic panel and the two ...
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2answers
239 views

Transistor switch for VFD tube grid

I am designing a on/off switch for the grid of a VFD tube, and I would like to use a NPN transistor. The requirements are: The Grid is on when 12V are applied. At this voltage, 0.85mA flow. I want to ...
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2answers
53 views

Motor with two endstops using limit switches

I have a circuit where two limit-switches to be wired with motors to do the following functionality. It is to be used in a remotely placed device so that the intervention of microcontroller on the ...
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1answer
35 views

Powering 3 DC motors (with limit switches) with AC-DC adapter

I have 3 DC motors: each motor is being used to drive an independent system of pulleys. This system of pulleys spins a threaded bar in order to raise/lower a shelf in a linear motion. Thus, I have a ...
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21 views

120 volt pond pump, trying to make the on and off work from an irritrol rain dial controller , from the pump switch [on hold]

120 volt pond pump motor is direct wired in to breaker. I have a transformer reducing to 24volts for a toggle switch. Seems as though I can't take wires from toggle switch and put on controller pump ...
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1answer
33 views

how to use a second power source to automatically switch on another

I'm working on a little car based project, where I have an inverter protected by a 40a internal fuse. I need this inverter to only recieve power when the ignition switch is on (i.e. when car is ...
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2answers
152 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 ...
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1answer
83 views

Use a momentary switch with a toggle switch

I've got a machine I'm making (A raspberry Pi with a picade Hat), which has a soft power off functionality (one click to power on, one click to power off). I'm putting it in a toy which had a key to ...
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1answer
52 views

Switch placement on electronic circuits on the positive wire

Why are main on/off switches in electronic circuits/appliances (any small, low power electronics) always placed on the positive wire (in case of DC circuits) between the power supply (batteries, ...
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1answer
41 views

Wiring an alarm to continually sound when activated

I'm working on a basic window-switch activated alarm that runs on 12v. When the window is opened, the window switch activates the alarm sounder. The issue is if the window is immediately closed again,...
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2answers
2k views

Three legged NOT gate? What is this symbol?

I've come across the above schematic in a datasheet for a 4x2:1 bus switch. What exactly does that triangular symbol on S mean? It looks a lot like a NOT gate, but ...
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1answer
84 views

Momentary Bosch Style Relay with Changeover

I know this is probably really common electrical engineering knowledge, but I am not an electrical engineer so I am quite lost on this. I have a 2004 BMW and the fog lights work something like this: ...
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1answer
124 views

How to multiply a voltage when its lower than 5V?

I am working with a power source of a range from 0-20V and I need to regulate the voltage to 12V. I plan to use a buck boost converter to stabilize the voltage, the problem is the input range is 5-32V....
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1answer
301 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 ...
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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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2answers
110 views

Variable voltage switching 12vdc

I am looking for a circuit that would be switching a relay coil and few small leds (max 3A) with a low voltage input. Now the input is variable voltage 1.1v to 5v produced by a hall sensor pot. I want ...
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2answers
459 views

Switch on off using triac BTA24, When off keep flashing LED lamp

Friends have a simple circuit a switch on off using triac BTA24600B, The strange fact is that when I turn off my led lamp keeps flashing fast, this is not the case with other types of lamps, only with ...
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2answers
597 views

Analog switch with a fixed state when not powered?

I am looking for a chip that could handle DPDT (or SPDT, or ultimately SPST) analog switch for audio routing (in the mOhm range resistance) and can guarantee one state when there is no power supply. ...
2
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1answer
84 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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1answer
34 views

Question about a charge injection compensation network for analog switches

I'm studying this kind of CMOS switch: With the switch in Fig. 2.17 in the on state, after a transient, we have Vout=Vin hence the drain to source voltage of M1 goes to zero. The MOS enters the ...
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1answer
47 views

How to read this switch data

I'm come across a schematic that uses a switch symbol shown below. This switch is a Kraus & Naimer CA10 Switch (That's all I know). The schematic symbol is shown on the right with terminals ...
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2answers
89 views

Question about analog switch

I'm studying this kind of CMOS switch: I have some doubts about some sentences of my book. 1) "For many analog applications, a switch is used merely to transfer a charge from one node to another ...
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1answer
104 views

How do I use a switch without current running through it?

So there have been plenty of occasions where I would like to use a switch or even potentiometer in simple circuits I make (just little at home hobbyist creations). But alot of the switches I try to ...
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3answers
144 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 ...
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2answers
3k views

Why do we need a voltage divider when we get the same voltage at the output as the input?

I am using a voltage divider circuit of 100 Ω and 10 kΩ resistors, and using their output for the (IRF740) transistor's input. I'm trying to figure out why do the resistors have those specific values....
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1answer
28 views

Solid State relay and Limit switch

I'm building my first CNC machine, it's a 40W Laser Cutter. I'm planning on adding a security feature that cuts the laser power supply if the enclosure door is open during while operating. I want to ...
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3answers
2k views

Momentary-Pushbutton Latch Switch with off delay?

I am trying to construct a latching circuit with a 1-2 minute shutdown delay so I can soft start/stop a 240V-5V power supply. I am looking for a momentary push latching (on-off) circuit to switch the ...
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1answer
96 views

How to connect switches to power transformer?

I'd like to use two rocker switches, each is single pole and including a light bulb on the inside (230VAC) to control the powering the system. I'd like to connect both of them to the transformer with ...
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0answers
32 views

How to implement a switch in spice? [duplicate]

I have designed a circuit where I want to give a pulse of very short duration using a switch. How can I implement it in spice.
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1answer
441 views

How long does it take for electricity to be considered OFF by general appliances?

I'm looking for an ATS (or DIY) to switch between my solar and grid power. I've seen some automatic ATS like here I've seen on youtube someone uses this model and his computer is switching between ...
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1answer
52 views

12V DC Switch Connection?

I have a 12V and 20A LED switch,but I want to switch 24V DC with this switch.Is it possible to turn on the LED on the switch and also switch 24V DC?
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2answers
156 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 ...
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2answers
115 views

How to use Arduino to control the switch on a 4.5v circuit

I've been building a wall mounted lightsaber using the below board. At the moment the switch is turning it on and off, however I want to automate this with an Arduino. Can I use a digital output ...
2
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1answer
88 views

What device can switch ON and OFF different pads independently?

I am looking for a device, but I am not sure what I need: maybe you have ideas. I have a power supply connected to 16 electrodes. What I need is a device (see picture) between the power supply and the ...
5
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3answers
18k views

A good circuit for a large number of push button inputs?

I'm planning to build a kid-friendly "universal remote" so the kids can turn on and off a myriad of IR-controlled devices with one or two easy presses... The remote is going to have maybe 20 big ...
5
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2answers
1k views

2n2222a as a Switch

I just connected a very basic transistor as a switch circuit, and was trying to control it with a function generator with a schematic shown below. simulate this circuit – Schematic created ...
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2answers
40 views

Switching multiple photodiode inputs to an op amp

I am playing around with LEDs as (semi)wavelength selective photodetectors and have reproduced the circuit found in Forest Mims' Make article: I have an operational circuit using an LM358 powered by ...
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2answers
133 views

How to keep users from breaking push button switches

I'm designing an enclosure for a device with a push button switch. The external button on the enclosure is physically large so I am concerned people will apply too much force and break the switch or ...
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1answer
110 views

Advice on choosing PCB for a 16A, 85V switch circuit

I am making a circuit that will allow a load to be configured in this manner: Load is ON/OFF. If OFF (controlled by a low-side FET making the circuit OPEN), the high side and low side can be ...
0
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1answer
97 views

2 Phase zero time switch

I'm trying to build an instant or zero 2 pole switch (DC current). Basically what I'm trying to accomplish is that when the switch is powered off, the lines are connected like shown in the first ...
1
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1answer
202 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 ...
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0answers
25 views

On/off circuit from single (NO) momentary push button with emergency off from another (NO) momentary push button using a relay

I'm trying to have a failure proof power off from a normally open momentary push button, which I am going to call it S2. What I mean as failure proof is that S2 must turn power off. So, preferably no ...
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2answers
47 views

Safe to turn variable speed AC motor on/off via wall switched outlet

I have a (high velocity air) dual AC brush motor pet hair dryer (details). (There is no heating element.) It's rated at 120 Volts 18.5 Amps. It has a rotary knob (listed on the parts page as a "...
0
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1answer
89 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 ...
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5answers
1k views

I want to know the name of this below component

Its a turn Knob switch for setting timer and push start in Samsung microwave oven I also want to desolder this component. How to do that? https://www.buyspares.co.uk/microwave/mw87l-mw87l-bxeu/assy-...
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1answer
451 views

2n2222 NPN low side switch not working with 31V

I'm attempting my first slightly more advanced circuit and failing. I have a led string which I'm powering with a 31V 0.21A power adapter that came with it. Now I'm trying to switch it on and off with ...
2
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2answers
238 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 ...
0
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1answer
80 views

Why does this amplifier not work past a given Vcc?

This circuit works well enough in simulation, I've built it and I can't get the final stage to put more than around 16V across the load. The last stage itself is performing like a voltage follower in ...
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3answers
15k views

Operation of infinite switch

Many electric stovetops are operated by an infinite switch, which pulses the current on and off for intervals determined by the dial setting. The actual control is effected via a bi-metal switch that ...