Tagged Questions

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

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3
votes
3answers
72 views

Energy efficient one button on/off with extra function

(Old) cellphones have a button to turn it on (when off), end a call (when on, short press) or turn it off (when on, long press). I need something similar for a microcontroller. The device is ...
6
votes
4answers
99 views

Can I achieve a one shot button without a 555?

I have a complex circuit, but my problem only relates to one small part. I have a relay, which is energised by pulling the low side low using an NPN. I would like a pushbutton to operate the ...
5
votes
1answer
99 views

Circuit that switches one led ore all three

For an analog photo enlarger (yep, that vintage stuff) I own, I would like to build my own lightsource. For the prototype I found 3 colored super bright led panels they use 12V The problem is that ...
0
votes
0answers
25 views

over temperature and current limiting question about a power switch: BTS5235

I am designing a cuircuit with BTS5235-a smart power switch from infineon.this is the datasheet of BTS5235 I get realy confused about its datasheet. 1.problem about VDS(Voltage at power transistor). ...
3
votes
1answer
69 views

Electrical properties of keyboard keys

I'm looking to hack together a keyboard by taking an existing keyboard and connecting it to switches that I'll assemble separately. What I want to know: What should be the electrical properties of ...
1
vote
1answer
52 views

Wiring a switch to toggle both usb power and external power on Arduino

I have a 5v Arduino Pro Micro. I am using it to run a series of motors. I am controlling it through the USB port. The USB power doesn't supply enough current to power the motors, so I am using a 9v ...
2
votes
2answers
71 views

Best practice to switch +V or GND connection?

Consider LAMP1 and LAMP2 in the simple example circuit below: Which is the "better" practice, using the switching component ...
4
votes
3answers
128 views

Why does grounding my switch cause the fuse to blow?

I'm working on restoring an old ATV, and I'm having a bit of trouble with the wiring. When I got the ATV it was missing the ignition switch, so I decided to replace it with this awesome looking ...
0
votes
1answer
54 views

Any Ideas for Understand one of the 3 phases has powered

I want to ask you about a situation which i couldnt find the exact solution or better way to do the job. The situation is i have 3 phase (380V) induction motor and one of the phases to the motor had a ...
1
vote
2answers
70 views

Max switch current

I am in the process of designing my first PCB and I need to include some switches to open or close a circuit with a max current of 500mA at 5v. I have found a DIP switch that I want to include on the ...
2
votes
1answer
93 views

Diode selection for truck wiring light application

I need to know what diode I need for a light set up I am working on. The main current flow through the diode is going to be 9v going to power a 55watt roughly ??? amp bulb. There will be ocassional ...
1
vote
1answer
52 views

Default-on, latch-off, MOSFET power switch

I'd like to build a low-battery circuit. It should default on when first connected, but if a particular signal goes high for a small amount of time (say, 10 microseconds,) then it should turn off, and ...
3
votes
3answers
196 views

MOSFET as a switch?

In the picture shown, can "Output" be controlled to be 0V or 12V based on "Control"? Will be Drain and Source the way it is connected be a problem?
1
vote
1answer
100 views

How to switch between a solar panel and battery?

A 12v battery is being charged from a solar panel. When battery is 12v solar panel is disconnected from battery and connect the load with battery. And again solar panel is connected with battery when ...
4
votes
3answers
70 views

Creating a Sequenced Array of 3 Mosfets with Adjustable Timings

I am comfortable with rudimentary 555 circuits and other basics, but I have something a little bit beyond me now. I need to have three separate mosfets A, B, and C all turn on and off in sequence. I ...
1
vote
5answers
212 views

MOSFET or Transistor for using as switch for audio signals

I was wondering which component is better for using as voltage controlled switch for audio signals (e.g. music signal from mp3 player). Should I use MOSFETs or transistors? The max rail voltage is ...
3
votes
2answers
209 views

BJTs versus (MOS)FET to switch a load from a microcontroller

I would like to know what are the reasons for choosing bipolar junction transistor (BJT) versus a field-effect transistor (FET) (MOSFET or a JFET) to switch a load from a microcontroller. In our ...
1
vote
2answers
80 views

easiest way to detect a switch change using an arduino

I have a pinball machine thats an old electro mechanical type. I want to add LED's and do some fancy programming on an Arduino to animate the lights according to the score value of whatever target ...
0
votes
2answers
53 views

2 x 4:1 Switch or Demultiplexer

I have 8 LED's and I am trying to turn 2 on at a time. My voltage source is 5V and the LED's require up to 200 mA current. I am finding quite a few demultiplex chips that are 2x4:1 but most of them ...
2
votes
2answers
119 views

Is this a 5V to 3.3V level converter?

Need to repair a legacy system that has been discontinued and am confused by the PNP based circuit below. The input signal (max. freq = 20Khz) is applied at IN and is active low. It's TTL level. It ...
0
votes
1answer
57 views

Connecting three led transformers

I'm a furniture maker and I built a unit which used three circuits of led lights. Each circuit's transformer has a max output of 2.5 A. I would like to use a single switch to put between the plug and ...
6
votes
4answers
212 views

Protecting Microcontroller Input Pins from Soft Power Switch

I'm working on a soft power switch for a microcontroller where a momentary switch can turn the circuit on (including microcontroller), and then when the switch is pushed a second time, the ...
2
votes
2answers
77 views

What is the best way to switch between different ranges when designing a multimeter using microcontroller?

We are developing a multimeter using a PIC18 microcontroller and we are searching for the best method to switch between different ranges in multimeter with the smallest possible amount of switching ...
0
votes
2answers
98 views

Representing a four-way light switch

I've found symbols in this explanation for a four way switch but I can't find that symbol in any of the online circuit-drawing tools I've looked at. The best alternate representation I've come up ...
0
votes
1answer
57 views

I think I am looking for a specific DC relay switch

I looking for a switch not sure what kind though. let me explane: I have 2 sources one creating DC 12v, 2 one creating around 6v DC One source works for about 12 hours each day then stops the other ...
0
votes
2answers
69 views

iCMOS analog switches and multiplexers

Does anyone have any experience with Analog Devices iCMOS high voltage analog switches or multiplexers like the ADG1434 or ADG1411? The specs for iCMOS sound very impressive. But they've been ...
3
votes
1answer
184 views

Is it possible to use just a capacitor to debounce a button?

I have been wondering: why cannot you just hook up a capacitor to a button to debounce it? I have been figuring out how to reduce the work my microprocessor has to do, but I have very limited space on ...
6
votes
2answers
137 views

How do these modern power buttons on devices work

In the older days and still now we have buttons where one way is off and the other way is on, its mechanically built to connect or disconnect an electric path physically. On modern devices like ...
1
vote
1answer
71 views

Turning the PN junction of JFET on?

I am going to use a N channel JFET as a normally-ON switch. I am wondering if it would cause any problem in the long term reliability having the PN junction forward-biased. In other words, would it be ...
0
votes
0answers
74 views

Controlling Wall Switch

I intend to control the operation of a wall switch through an arduino board. I'm wondering if there's a good way to wire into this switch to do so, or if I need to go farther back. Here's the switch ...
7
votes
3answers
392 views

Pull Switches - why so expensive

I would like to use a pull switch as a trigger for an alarm that I'm building. When the switch is triggered it will turn on a siren and potentially a strobe light. I've found plenty of options out ...
-5
votes
1answer
58 views

How to build a switch that is turned on with small voltage? [closed]

I want build a switch that is switched ON with 1 or 2 volts. A small circuit would be fine.
2
votes
0answers
189 views

Arduino - Trigger an iPhone's touch screen with no human interaction

I'm trying to replicate part of this experiment. Specifically, I want to touch the screen with a cable and some aluminum foil whenever I send a signal from an Arduino pin. From the blog post linked ...
3
votes
1answer
100 views

Switches needed in an n-location multiway switching system

Wikipedia shows us we can construct a two location multiway switching system with two 3-way switches: They also teach us how to perform three location multiway switching with two 3-way switches and ...
0
votes
2answers
57 views

How to block/allow an i2c data signal to pass on to another device

I have three devices which I'm working on and one of them needs to control i2c communication between the other two. Each of the devices is based on an AtMega or AtTiny chip. The Controller (based on ...
0
votes
1answer
59 views

Single FET Bus Switch schematic in EAGLE

I've added a SN74CBT1G384DBV into my schematic in Eagle (which I want to use to enable/disable a logic signal line). Once placed into the schematic there only appear to be connection points for VCC ...
-1
votes
5answers
202 views

how to automatically reverse the direction of a stopped gear motor and restart 12 hours later

The reversible gear motor needs to turn on @ 6:00 am pull a object 12 inches and shut off. Twelve hours later the gear motor needs to turn on and reverse the direction and place the object back in ...
2
votes
2answers
93 views

Does it exist: Latching Relay with Manual Switch

I'm looking for a latching relay (so I can control its state remotely) with a manual switch (preferably with a rocker style switch, so I can control its state locally). Do these exist as I'm ...
1
vote
1answer
108 views

How to switch light on by standing on a mat

I'm working on a project for school. And I have this dance matt. As long as you stand on that matt the light should go on and stay on until you step off the matt again. But I have no idea how to make ...
0
votes
1answer
50 views

Need faster analog mux. Use switches and summation amp?

I need to alternately sample 64 channels at 20Ms/s. That's 50ns per channel. I used to have a slower version at 2Ms/s and there i used 1 ADC and a series of analog muxes. This time around, at ten ...
4
votes
1answer
165 views

Wiring an illuminated toggle switch

I'm trying to build a model rocket launcher circuit. So far I have this The igniter requires 12V and 3A, BAT1 is 12.6V 9800mAh. The arduino input pin should read HIGH when the igniter is connected ...
0
votes
1answer
119 views

Solid State Switch for magnet DC Generator

I'm using a flywheel-driven permanent magnet DC generator to charge up a bank of supercapacitors, 35 farad rated to 25V. For safety I limit the max charge to 22V via a comparator and a zener ...
3
votes
2answers
282 views

Do I need to use a resistor with a microswitch to limit current for an Arduino Uno?

I'm using an Arduino Uno to control a small robot and I'm starting to add micro-switches as bump-sensors. I know that when I'm creating a circuit with LEDs I need to use resistors to limit the current ...
1
vote
0answers
88 views

Lighting relay(?) with 220V leakage insensitive coil

Existing staircase lighting time-automat can not use 220V neon mini-bulb or LED lighted make-contact buttons. - These convenient buttons cause it t false-start (as if pressed) due to their ...
0
votes
1answer
104 views

Beaglebone GPIO always return 1

I'm trying to get a button to work on my Beaglebone. I bought MAKE Volume 32 and tried to follow the guide in there. But when I read the GPIO pin, do I always get 1. I also tried to disconnect ...
0
votes
2answers
92 views

Can I use a silicon controlled rectifier to discharge a capacitor?

Can I use a silicon controlled rectifier to discharge a capacitor? If yes, can you provide a diagram of how this would work in, say, a coil gun?
2
votes
4answers
145 views

10 million cycle mechanical switch

I've been working on my electrical switch with 10 million cycles lifetime, and changed the design from using mechanical contact to hall effect sensors as per the advice of stackexchange. However I ...
2
votes
2answers
444 views

Wiring a SPDT Relay

I am new to Electronics and I am currently trying to wire up a SPDT Relay. I must admit I am totally confused. I want to have a SPDT switch that simply switches the relay over. Any pointers would be ...
-2
votes
1answer
141 views

Replacing an illuminated rocker switch with 2 terminals [closed]

I am trying to replace a burnt out illuminated rocker switch in an electric fireplace heater. I ordered a replacement switch that looked like it would do the trick, but failed to notice that it had ...
1
vote
1answer
139 views

Build an Audio Toggle Box

I want to build a small box with two audio inputs and two audio outputs, with two switches to control the current input/output. Something like this: http://www.youtube.com/watch?v=mQzLnt0_-zU I've ...

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