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Questions tagged [switches]

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

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0answers
33 views

Touch switch for LED lamp

I would like to see if possible to use a mosfet like the irfz44n to do the job as a touch switch... off-course it will need a few more components, but my drawing has the general idea. the lamp already ...
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0answers
51 views

Led on for one minute eve if the switch is pressed for more than one minute? [duplicate]

how to make a circuit that when press the switch the led is gonna stay on for one minute and than off even if the switch is still pressed for more than one minute
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1answer
138 views

How to analyze RL circuit with sequential switching?

I am trying to solve this question: However, I am having difficulties solving as I only have come across circuits which are initially closed then opened, not vice versa as is the case here. ...
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3answers
134 views

Arduino logic level mosfet

I am currently trying to switch on a nichrome wire for about 5s using an Arduino and an external power source. It will be a single use only activation, I have decided to use an N-Channel mosfet for ...
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2answers
82 views

How do I make a circuit for a push switch that in order to turn on you need to press it 2 times?

Is there any way to make a switch circuit that turn a led on by pressig it two times thank you...
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2answers
125 views

Use transitor as a switch to ground audio input

I have got a probably very dumb question. I was not able to find an answer on the other topics because they always described the use of transistor as a switch for other applications. I have a ...
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2answers
63 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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1answer
91 views

New to circuits: Creating a toggle button in Logisim using Latch

I have just started doing logic and circuits and I am trying to make a toggle button using a button and a latch. I can't seem to figure out how to make the light toggle instead of turning on when the ...
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2answers
68 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 ...
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1answer
141 views

IGBT contactor design

I found this circuit in an older post. I was thinking about using this in place of a contactor to break under load. The load would be at 500V 300A DC. There would be overcurrent protection in line ...
0
votes
1answer
60 views

Under what conditions can Vbe exceed 0.7

I am simulating a transistor switch in PSPICE. The goal is to switch a load (like a lamp) connected in the collector on and off. Imagine that in the place of the R2 resistor there is this ...
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2answers
71 views

Ignoring switches in a device

I'm assembling a bluetooth speaker as DIY project. i'm stuck with bluetooth receiver module which have inbuilt push button (hold for 5 sec) to start/stop the bluetooth receiver. I want to ignore that ...
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2answers
79 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
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1answer
61 views

In Charging Circuit with battery detection

The circuit is charging the battery with Vcharge and VCharge also power up the circuit operation. Battery will serve to power the circuit when main power supply VCharge cut off. A switch is added to ...
2
votes
2answers
252 views

Auto turn off switch during power outage

In my area power outages are a daily routine. And power surges, which occur when the electricity comes back, makes it even worse. To avoid damage of the electronic devices we try to unplug them ...
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1answer
55 views

Enable one or two of the same output via switch (minimalist schematic)

I'm making a PCB and my real estate is limited. I am using an AT89C2051 microcontroller, and it only has one serial transmit output. What I need is a way to set whether the output from the serial ...
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2answers
431 views

How to measure switch bounce on a CRO?

I want to measure switch bounce, but all I have is access to an old CRO. Based on inputs from this forum post, I tried the HOLDOFF knobs and other buttons too. Nothing worked. In the case of modern ...
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1answer
74 views

How to wire a 8-directional switch (Alps RKJXW)

I would like to use the following component in my design: https://www.alps.com/prod/info/E/HTML/MultiControl/Switch/RKJXW/RKJXW1014002.html This is a 8 way directional switch with push button (it ...
4
votes
1answer
117 views

Induced power supply noise on switch contact

I have a circuit that has a 24V section and a 5V section, separated by opto-isolators and an isolated DCDC converter. Both sides of the DC-DC have decoupling caps, and the MCU has one per Vcc pin. ...
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1answer
97 views

Some questions about a low frequency reed switch interface circuit

I need to wire this reed-switch rain-meter sensor to a counter input or to an isolated analog input channel of a data acquisition board. The sensor will be around 30 meters far away from the data ...
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2answers
65 views

Different logic levels on single input

I have a circuit that has about a 1V input that gets boosted to 3.3V. To enable the boost converter IC, a switch is pressed which causes the enable signal [EN] of the converter to go high (and stay ...
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0answers
53 views

How to find SPDT IC that doesn't need a power-supply to have NC and COM connected?

I am looking for a SPDT IC (or circuit?) that connects NC and COM even if the power-supply is off. Basically, I need a TS5A3157 without the need of a power-supply in the NC state. The reason for ...
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0answers
44 views

Multiplexer Configuration for Switching Audio Effects Loops

I'm in the middle of designing a guitar pedal that digitally controls the routing of audio between different effects loops using switches. I am having a hard time figuring out what hardware//...
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1answer
49 views

Looking for a component that lets me choose where to draw power from [closed]

I would like to have a switch or box that allows me to plug a battery and wall power into the box, and then has a switch that chooses which power to use for the output. The ideal inputs of the box ...
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2answers
157 views

high side MOSFET switch and BJT interface with MCU GPIO

im operating a 28V contactor using a GPIO from my MCU, i have a 28V supply readily available. im looking to surpass the gate threshold of the MOSFET by introducing a NPN BJT with a 10V supply, with ...
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2answers
67 views

Operational Amplifier Integator

I want to design op amp integrator circuit with variable time constant using a simple switch. What is the typical shunt capacitance of a switch? I assume Ron of switch to be less than 5 Ohms. I want ...
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4answers
111 views

Circuit to get a short at 0 volts and open at 3.3/5 volts using transistors

simulate this circuit – Schematic created using CircuitLab This is the situation I am trying to solve. I am considering using a transistor, but am not 100% sure. When I get a 0 volt input, the ...
1
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1answer
86 views

MOSFET as switches in non ohmic region

I have a project in which I have to "close a digital switch" using either a 5V or a 3.3V supply. The load will be at 12V, with a required current of around 200mA. As a newbie I thought to use an N-...
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2answers
81 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 ...
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0answers
37 views

Power distribution for low power application in a tight package for wearable

I'm looking for a component that will allow me to switch on/off the supply power to my onboard peripherals. I have a design that requires the peripherals to be powered only when they are in use to ...
0
votes
1answer
50 views

How do I turn on a device with one momentary switch and off with another

I've got this rev limiter I'd like to engage with one momentary switch and turn off with another (momentary) one. It would be turned on or off for extended periods of time. Ideally, this contraption ...
2
votes
2answers
99 views

How can I build a battery load tester that switches between 0.8 and 2.0 ohms? [closed]

I would like to build a load tester that switches: 2 seconds at 2.0 ohms and 1 second at 0.8 ohms and back to 2.0 ohms to repeat. I gather that I can have a circuit with two resistors and a switch ...
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1answer
85 views

Snubber Network Over a Switch

I'm a newbie to electronics even though I have been working on them for a few years in mostly a hobbyist setting. I'm posting here for the first time so please be gentle. The problem I'm having with ...
4
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2answers
232 views

Is this resistor necessary for protection?

I would like to incorporate this circuit in my design so that I could use a low current capacity slide switch to control the 2A current of a Li-poly. Now, I understand the purpose of having two PMOS ...
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1answer
220 views

How to switch composite video signal inputs to one output

what I want to do To switch composite video signal inputs to one output. conditions 4 inputs to 1 output all inputs and output are composite video signals with RCA connectors 12VDC used for power ...
2
votes
2answers
90 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
127 views

Momentary Switch NAND Latching IC Burning and (Possibly) Faulty Logic

Problem: My issue is that the momentary switch with NAND latching logic that I have designed is not functioning consistently. It does work as intended at first, but then fails to work after repeated ...
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1answer
118 views

Power multiplexing with low leakage current for low power applications

I have a scenario in which one of two power sources is selected by a power multiplexing: One solution is to use already existing mux ICs like TPS2115A. The problem is that the leakage of these ICs ...
0
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1answer
35 views

Bypass Gate-to-trigger-converter via switching jack

Goal I like to trigger a LF398 Sample-and-Hold IC via a 3.5mm Jack (modular synthesizer). The desired behaviour would be: if a cable is plugged in, incoming signals will be converted to short ...
1
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1answer
86 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 ...
0
votes
1answer
67 views

Right way to connect leds to light up when pressing buttons

I want to connect leds to Cherry MX switches (push switches) so they light up when I press them. I have 6 switches each connected to a different pin of a teensy 2, basically like this: The diodes ...
0
votes
1answer
39 views

Magnetic switch, master/slave socket and dust collection

I have a dust collection (JET DC-1100CK) and table saw. I bought a 400V master/slave unit, connected all together and it does not work. I talked to the JET seller and he told me that the dust ...
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3answers
134 views

Keep a circuit closed after activating a reed switch NO (normally open)

I need a circuit that it is open until I bring near a magnet that closes a NO reed switch for a short interval of time. I need the circuit keep closed for ever. Thanks!
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1answer
44 views

Feedthrough capacitor in analog switches

I'm just wondering if anyone knows what feedthrough capacitor is, and how it can affect our switch. As far as I'm concerned, if we use FETs as switches, feedthrough capacitors are the one that ...
1
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1answer
72 views

How to hook up a fan to this switching circuit

I am trying to build a controlable fan with a raspberry pi and I have found the below circuit for a switching circuit to allow the 12V power to go to the fan My question is how do I then hook the fan ...
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0answers
37 views

2 Light Sources into one Power Source

So to start I'm uncertain if this will seem like a lot or easier than I'm making it out to be. The premise is that I am making a marquee tattoo parlor sign with a very flashy theme, consisting of a ...
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2answers
55 views

How do series connected lamp dimmers/electronic switches work?

How does a series connected electronic LED lamp switch operate when it has switched the lamp off and there is no voltage reference. And how does it work when the lamp is switched on and the voltage ...
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1answer
167 views

NMOS analog switch

I have this circuit taken out from a book. The book says that :"The circuit as shown will work for positive signals up to about 10V; for larger signals the gate drive is insufficient to hold the FET ...
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1answer
106 views

Microwave oven with no heat, Bad design or wrong component choice? [closed]

Few days ago, my Magic Chef MCD990B microwave oven magically passed away randomly and so suddenly that I didn't even have time to say goodbye, not that I have used it heavily or considered it as my ...
1
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1answer
334 views

Latching Press-on / hold-off toggle switch circuit. Works on breadboard not on PCB

I followed a schematic and mocked up a Latching toggle switch with NAND gates. (see picture below for what I followed) (Source) I have mocked it up onto a breadboard. Using the exact same values of ...