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

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50 views

How do I get multiple voltage lines from a single PSU output?

Suppose I have a regulated power supply that has +20V and -20V outputs, and an amplifier circuit that uses them. I also have a push-button (not momentary) power switch with an integrated LED which ...
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0answers
21 views

MCP23017 not causing interrupts using a normally open switch on power up

I'm working on a project where I am using two 4x4 button pads. I would need to use two MCP23017 for input interrupts to support the 32 buttons. I am using a Netduino and I'm coming across an issue ...
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1answer
53 views

Reducing transistor switching time with a resistor from base to a negative voltage

Connecting a resistor from the base of a transistor to ground/negative voltage (R in the first scheme below) helps reduce its switching time. I would like to know why and how does it help; what are ...
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5answers
238 views
+50

MOSFET PWM switch jamming on - why?

The circuit presented here is sized to switch 100W at a minimum pulse width matching 250Hz. But actually it's currently only being asked to switch around 10-20W. The load is an array of LEDs. Q1 ...
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1answer
53 views

Changing the path of a signal through multiple transistors with a single-poled switch

I was wanting to construct a "fuzz" distortion guitar pedal, but being indecisive, I wanted to be able to change the type of transistors in the circuit at will. I found the idea of using a ...
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0answers
27 views

Using 3 Channel Video Switcher Module with Arduino

Hey all I am wondering how to go about switch from camera 1, 2 or 3 using this 3 Channel Video Switcher Module on ebay here. Since there's only V+, V- and signal for the "switch" it looks to take a ...
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2answers
48 views

Question regarding SPDT switch

I'm looking for a particular type of mini SPDT switch, it has 3 poles (if memory serves correct, could be 2 pole) and has 3 total positions. By default it's centered and is set to an off state. If ...
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3answers
63 views

Can I use a switch rated as 250VAC 25A to switch 50VDC 25A?

I am looking for a switch that can handle 25A continous current, the voltage will be maximum 50VDC, most often about 46VDC, and it will be used to switch on two dc-dc converters that have no load ...
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3answers
137 views

Using a P-channel MOSFET as an on/off switch

The project I want to build is shown below. I want to operate the P-channel mosfet on and off with variable frequency from 20-100Hz and I choose P-channel to do this so that the +350V will not be ...
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3answers
92 views

Audio Signal Switching - “DPDT switch vs. 4066”

I've got a signal coming from an electric guitar and I need to switch it. Basically it's a distortion circuit. I need to switch between the distortion and clean (directly connected to the output) My ...
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1answer
35 views

Replace LED by a Trasmitter

I need a wireless switch with capability to report current state, so I would like to modify a wireless switche like this, by replacing a current state LED by a trasmitter to get the state of current ...
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1answer
33 views

Can you use a SPST to turn on and off two power sources?

I have several batteries in series and the ground point is in the center, such that I can achieve a negative and positive voltage. The OP amp uses both negative and positive voltage. Let's assume I am ...
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1answer
57 views

Wiring an IC for VGA switcher

Original schematic: Here is the goal switch between two VGA outputs from one source VGA input. Parts list: 1 SPDT switch for switching between A or B video outputs. 2 CBT3244AD IC chips (here's ...
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1answer
90 views

Can one be electrocuted when cleaning a light switch? [closed]

Light switches are allegedly some of the dirtiest spots in a house, and cleaning them is recommended in many articles. However the safety angle doesn't seem to get coevered. The only thing I could ...
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2answers
53 views

Switch not working as expected

I have what I think to be a DPST switch. My problem is when I plug it into my circuit, it seems to be closed regardless of whether I press it or not. I have tested with another of the same type of ...
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0answers
30 views

Power management in battery-based Arduino

I have an Arduino-based project which uses external sensors, communication chips, and displays. While I can place the Arduino into a low-power mode, this does not change the power consumption of the ...
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1answer
58 views

Use Arduino for switch a 12v powered remote control

I've a remote control powered by a 12v battery. I need to switch a button using arduino, can I use directly the digital pin without any relay or transistor? Thanks in advance
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2answers
103 views

MOSFET source to drain Current

Since similar kind of questions being asked before it.. They doesn't clarify how one can use it in circuit. I'm aware that a MOSFET is a bidirectional device and in one direction current can flow ...
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2answers
52 views

Trying to identify this rocker switch in a KRK speaker

I am trying to replace a broken (the rocker arm was pushed in) rocker switch on a KRK V4 speaker, and am looking for a suitable part number. I don't see a number on the switch and don't want to take ...
3
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1answer
467 views

Turn 9V device off using 3.3V logic level signal

i'm facing the problem to turn a 9V (battery) powered device OFF using the output of a 3.3V based microcontroller. To do this i already threw together the following circuit (which works - assuming i ...
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2answers
172 views

Jack barrel contact diagram?

I've come across this diagram, I researched a bit, but I don't get what this contact is supposed to do. The circuit below is an audio effect, and I'm confused because it apparently doesn't mean that ...
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3answers
74 views

Which diode to use on my RC switch debounce circuit?

I am choosing parts to build an analog RC switch debounce circuit. I plan to implement the circuit described here: http://www.ganssle.com/debouncing-pt2.htm (see "An RC Debouncer"). These are the ...
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1answer
69 views

Inductor held with hands

I have a fairly simple problem, but as I am a newbie in electrical circuits I was hoping someone might help me understand the principles of things. I have a circuit with an inductor of L = 0,102H a ...
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0answers
62 views

How to control a bulb operating on 230v using a switch operated at 5v

Hello Electrical engineering community, Maybe this is an easy question to answer but I am new to this so definitely need assistance. I want to control a bulb which is driven via 230v AC mains using ...
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0answers
47 views

How does this circuit work?

http://www.pcbheaven.com/circuitpages/Resistance_Touch_Button/ This is a very simple touch switch. I understand the basic working of this circuit but there are a couple of things I want to understand ...
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1answer
36 views

How can I switch multiple circuits using switches with limited pole counts?

I am trying to refine the design of an audio switch that I built a while ago. Since this is used to connect two inputs (two sound cards) to five possible outputs (speakers, tv, etc) with stereo audio ...
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1answer
50 views

Running a load off a solar panel connected to 2x 12V batteries.

I am having trouble figuring out what relay I should be using for my solar panel set up. I have a solar panel running to a solar charge controller. I then have the controller running into a relay. ...
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1answer
38 views

Make Bypass with Switches

I have the diagram below, but I don't understand how the switches are hooked up. Is that an special switch, or I can achieve that with an special connection? Thank you!
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21 views

SIM908 PCB Switch Current Contact Rating

I am working on a board with a SIM908 module. The board is powered from a 4.2V Li-po Battery. The user must be able to switch the board on and off with the aid of a slide switch. My problem is ...
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3answers
85 views

power selector switch [closed]

i'm still working on my usb meter. I still have a problem in my design, I would like to implement an external power supply and a battery. I was looking for a circuit that would switch automatically ...
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0answers
40 views

Two Sided Push Button Latch

so I have here a push button latch that is tried and tested and that works beautifully. But I need help making a variation of it that will switch between two circuits instead of just turning one ...
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0answers
40 views

Switch capacitor analysis without initial condition

The figure below is described as: C1 and C2 are the pumping capacitors but at given time and conditions of clocks (VCk and VCk'), C1 is being charged while C2 pumps its stored charge to CL (load ...
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0answers
57 views

MOSFET Behavior During Pulsed Operation

I am trying to use back-to-back MOSFETs/IGBTs to isolate my pulsed supply from my load. In theory, I will switch on the MOSFETs, and the pulsed supply will be attached directly to the load (but not on ...
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1answer
79 views

How do I realize this problem with a digital circuit?

I'm trying to design an indicating system for a vehicle if it crosses its speed limit. Of course I'd be using a potentiometer to realize the action of increasing speed. The input is given to the base ...
0
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1answer
35 views

Issues with Latching switch using push button

I'm trying to make a latching power switch based off this schematic (source: EDN) I emulated the circuit in Falstad and everything works like it should (link to simulation). However, it doesn't ...
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1answer
31 views

Ambient Light Sensor + Comparator

So I've been looking at options to create a way of controlling whether a flash will fire based on the amount of light in the surrounding environment. Early note: Everything has to be surface mount ...
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0answers
46 views

Relay is not isolating properly its sorrounding circuit blocks

It turns out I've been building up an elevator for a project (at College). In general terms, everything appeared to be correct, regardless that I hadn't simulated each part. I decided to begin with ...
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3answers
847 views

Is this a good way to debounce a switch?

There are plenty of debouncing circuits on the internet, but I couldn't really find one that fitted my needs / available parts, so I came up with my own, from what I had. There's nothing special about ...
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3answers
118 views

Momentary\Pushbutton Latch Switch

I'm trying to make a circuit that will latch on\off with a pushbutton. This is what I have, but the LED just stays on even though the current shows the latch is working. Thoughts? Thanks :)
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0answers
51 views

Driving multiple IGBTs with gate drive transformer

I am playing with a circuit I've been working on, which consists of a stack of 15 IGBTs connected in series. The end goal was to drive this "device" with a single toroid transformer, where the drive ...
2
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1answer
46 views

Automatic cut off after switch is pressed

I have a fun one for you. Here is my diagram: It's a 555 timer in a monostable one shot configuration. What I want to do is find a way to prevent the LED from staying on if the switch is held down. ...
2
votes
1answer
71 views

How to ON/OFF two fans with 3-state rocker switch?

I have a 3-state switch, It has 3 pins. It can have 3 state as you can see in the picture below. when it's off (i.e on O) the middle pin is not connected to ...
0
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1answer
67 views

Input protection circuit with P MOSFETs and SPDT for ON-OFF switch

I am making a circuit which may draw up to 3-4 Amps, so I am avoiding using a Schottky diode as fool-proofing it from incorrect polarity on the battery (12V, automotive style) input. I have used P ...
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1answer
132 views

High side P channel MOSFET power switch - gate question, and suggestions for my circuit?

My circuit is for switching a 12V battery to a load (LED lights, designed for automotive use), during my testing with prototypes, the lights consumed about 400mA, meaning they were ~5W LED products. ...
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1answer
72 views

Switch Vcc to Ground with a control bit

I have a device that is 1 ohm and it consumes 3Amp. I want to run my device in both ways and I have only one voltage supply. I want to switch ground to Vcc and vice versa with a control bit from mcu. ...
0
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1answer
67 views

Adding hysteresis to MOSFET used as a switch

I have a low-voltage detection circuit which I use to trigger one of two LEDs (green, and red) that is powered off of a +9V battery cell. As the battery discharges, its output voltage decreases, until ...
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2answers
39 views

Variable output PSU switch configuration

So I am designing a switchable voltage 9V/18V power supply and was wondering, what's the best way to switch between outputs, that's the current schematic I came up with: Original image size So my ...
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0answers
39 views

SC circuit equivalent

Can someone help me find the equivalent SC circuit for figure 3? Just like in figure 2 with its equivalent circuit in figure 1. I'm just confused with the drain of M6 connected to gate of M2 at node ...
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1answer
52 views

What is the current flowing through this switch?

I am looking at a circuit diagram like this: simulate this circuit – Schematic created using CircuitLab Switch 1 and switch 2 never are on at the same time (they alternate) I turn on S2 ...
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1answer
138 views

Why is my circuit not working?

I built a very simple circuit from a schematic I found online, but it is not working. It is a touch switch circuit in which I touch a metal object connected to the circuit, and the LED2 connected at ...