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

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2
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3answers
29 views

Difference between High- and Low- side switching of power?

Is there any real difference between high- and low-side switching? Assume: Switching is for on/off control of an object (My case RPi) Base/Gate can be driven to Vcc and GND
0
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2answers
62 views

DPDT switch using only transistors

I have seen a number of similar questions but no one ever seems to actually answer this question, so let me pose it a different way. Let's suppose I am stuck on a space ship (so I can't go buy some ...
0
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2answers
72 views

Uninterrupted current triggering transistor base

I'm still pretty much a electronics-beginner, I'm currently working on modifying a USB game-pad to use switches instead of buttons and I want LEDs to accompany the switches. The basic solution I was ...
0
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0answers
19 views

Switching a power supply for electroluminescent cable

I have some electroluminescent cable and it came with a battery powered inverter. I don't know much about the inverter, but I assume it's putting out about 100V at 1-2khz. I'm currently trying to ...
0
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0answers
28 views

Low Voltage Switch/ Cut off for 5S lipo

Hi Could anyone please provide a schematic with component specs/values for a Low voltage switch / cut off using a mosfet. I have a power supply consisting of a 5S lithium battery pack and its ...
0
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0answers
36 views

Momentary tactile switch ON when unit connected to AC power - circuit modification

I have an air conditioner unit that after plugging in the power cord to the power outlet is off. You need to press a momentary switch on the circuit board to power the unit on. Now I would like to ...
0
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1answer
75 views

Three questions about the use of a transformer in switching power-supply

In this document (an introduction to switching power supplies) a boost-mode switching power supply is presented: it has a simple inductor, diode, capacitor and load. Then (page 9) it is specified that ...
0
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1answer
41 views

12v Latching on/off switch with momentary function

I'm looking to control a flashing light unit in my car that has several selectable patterns. It uses basic 12v+ to power and a basic +12v momentary to switch to the next pattern in a logical list. ...
0
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3answers
93 views

Switch that is physically closed, and electrically opened

Is there a switch which a user pushes/actuates to close, and which can be reopened with an electrical signal, and which does not consume power to stay closed or open? E.g. the user pushes the "Start" ...
0
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2answers
79 views

Using a high resistance pull down resistor

I'm trying to make a circuit where closing a switch will change a GPIO from low to high, and I want to minimize current as much as possible to increase battery life. The chip I will be using is Nordic ...
0
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2answers
49 views

Operating regions of a transistor switch

So it is operated in either saturation or cut off region but in between these two there is linear region (the intermediate region between the LOW and HIGH states of the transistor) and the transistor ...
0
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1answer
65 views

Power Switching with Microcontroller

I am in the process of designing a device for a uni project. As a requirement, we are required to have a very low power consumption whilst in standby mode. Our plan for this, was to have our 2 x +-5V ...
1
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1answer
57 views

Adding a remote switch and battery to a 9 volt dispenser

I have an insecticide dispenser in my shop. The unit is designed to spray a short burst of insecticide once every 8 minutes. I have found I don't need this frequent of a burst and my thought is to ...
6
votes
2answers
234 views

How to switch an AC signal on and off with a BJT?

I built a phase shift oscillator and now I want to turn the output of the oscillator on and off using a pulse, generated with the NE555 IC. I am trying to do this using a BJT. I connected the ...
0
votes
1answer
51 views

Momentary Button as Switch

I have a project that uses a computer case and PSU, but not motherboard, to turn on the PSU, all we know is to put green cable to GND. The problem is the ON Button, it's momentary and I need to keep ...
0
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0answers
42 views

2-State Wall AC Switch [migrated]

What happens to load in electrical installation which is switched by 2-State Wall AC Switch, when switch is not fully in ON or OFF state, but in middle state? Can that middle state damage load or ...
0
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1answer
22 views

Timed motor switch

I'm very new with electronics and I'm working on a project, I need to make a motor go forward then after a few seconds reverse, then forward then reverse and so on. I found this tutorial (How to ...
2
votes
1answer
166 views

N-channel MOSFET connection

I'm studying this circuit below which in fact uses a N-channel MOSFET in a power line, with source at the supply voltage and drain at the load. Why the source is the input supply voltage and not the ...
0
votes
1answer
86 views

Switch on when power is off

I'm looking for unknown element U1, which fulfils the following requirements: When power is ON, there shall be no connection between P1, P2, P3, and P4, i.e. replacing U1 with air would work. (Some ...
1
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2answers
37 views

How do I connect 3 audio inputs with a switch?

I have 3 outputs from different audio sources via aux cable. I'm trying to combine them all into a box and have an easy way to change the audio source. If only one source is going to be used at a time ...
0
votes
4answers
79 views

Using frequency to turn a circuit on

I would like to run 3 circuits and turn them on based on a frequency input from an audio source. I would like to turn on a circuit at a mosfet gate for example with tone A at 100Hz tone, B with 1kHz, ...
0
votes
1answer
42 views

How to delay the transistor turning on using a photoresistor?

I am a beginner in electronics, my project is the following: I am trying to build a simple circuit to switch on and off my garden lights according to the brightness level. More to the point, I'd like ...
0
votes
2answers
39 views

Measuring Switch State using PIC

What is the best way to measure the state of a latching switch using a micro controller? Keeping in mind the voltage level of the input to the switch is higher then the maximum voltage input to a MCU ...
0
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1answer
39 views

Solenoid valves in series or parallel?

I already have the main solution and dosing solution tanks hooked up to each other, with solenoid valve S1 controlled by the liquid level switch through the DC power supply and DC/AC SSR (see image), ...
-4
votes
1answer
82 views

What are the resistances of the R1 and R2? How to compute? [closed]

This is transistor as a switch. I used KSP2222A transistor. How to compute the resistances! Thank you for any help.
0
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1answer
46 views

Photocell and Relay switch not working properly

I am trying to build a simple circuit to switch on and off my garden lights according to the brightness level. More to the point, I'd like the lights to turn on when it's dark and off in the morning. ...
1
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1answer
80 views

Using TTL logic, is it better to use a JFET or MOSFET switch for power?

Using a 3.3V (max. 8 mA) output pin off an Intel Galileo development board, I need to turn on and off a 18V DC motor. Is it better to use a JFET or MOSFET transistor?
0
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1answer
55 views

Analog Switch, switch a voltage that is ~0.5v higher than VCC

I've been looking into different Analog Switch ICs and it seems they always allow a switching voltage between GND-VCC. Now the voltage I want to switch comes from a different source than VCC. ...
0
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1answer
39 views

FET array - logical switch

This is the circuit I plan to implement to control a LED by a logic bit simulate this circuit – Schematic created using CircuitLab The datasheet of the transistor can be found here I ...
2
votes
2answers
78 views

Name or part for the kill switch on a model rocket launcher?

Is there a name or a part-number for the type of kill switch used on a model rocket launcher ? The switch is closed by putting the key (basically a metal pin) into the hole. Is there a module I ...
0
votes
1answer
27 views

Digital timer rated for incandescent load only — what would happen with a small motor load?

I have a small digital timer designed to replace a wall switch. As such, it runs on the 120VAC mains and has only a hot and a ground in (plus a switched hot out). Because it works without its own ...
1
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3answers
54 views

2 led on latching pushbutton NO arduino

I am looking to push a button and one led comes on when i push the same button again the first led goes off and the second light comes on. alternating lights each time the button is pressed. one ...
0
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0answers
38 views

wireless on/off switch for LED using RF transmitter reciever

i wanted to switch on an LED using an RF transmitter receiver like we can see in this video (https://www.youtube.com/watch?v=jeRtyOgf0mI), although i do not want the morse code application, i just ...
1
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1answer
22 views

Averaging switch sensor value

I have a float switch that has three possible positions- open when above the water level, closed when below the water level, and rapidly opening and closing (freq~=0.1s) when its near the water level. ...
0
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1answer
35 views

Error interfacing GSM with Atmega32 using UART Interrupt?

I am interfacing GSM with atmega32 using uart interrupts. I am using an external interrupt which is fired when a user press a switch and uart receive interrupt to receive the response of GSM. CODE: ...
0
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0answers
33 views

Switch Mode power supply and ADC measurements

I've got a controller, measuring on 4 channels, but I see the (~50mVpp)ripple of the power supply, when I oszilloscope the ADC pin. The adc values jump around too. I tried to add an LC filter, but it ...
1
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2answers
75 views

How can I detect which DC power source to send to an underwater camera housing?

I have a small problem and hoping someone can help: I am trying to design and build a reasonably universal underwater housing for some different cameras. there is a breakout box on the surface and ...
0
votes
1answer
28 views

hall effect sensor as a toggle swich for a 12v strip of LEDs

I'm trying to use a unipolar hall effect sensor as a power switch to turn off and on a 12V strip of LEDs, powered by a 12V 6.6Ah battery. I just tested the current draw of the LED strip with a ...
1
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3answers
94 views

Transistor as a switch

I am having a tough time here.I want to design a simple transistor switch (obviously operating in saturation) using 2N3904.I want to switch a current of 10mA. The part in yellow rectangle indicates ...
1
vote
2answers
79 views

How to emulate a switch on power line

I have a circuit with two DC power lines coming from BAT1 (1A) & BAT2 (2A) (two outputs of a power bank). There is a sliding switch on the power line of BAT1. I would like to keep only one switch ...
2
votes
3answers
261 views

Where to place debouncing circuit for remote mounted buttons and rotary encoders

I have an application where a push button and mechanical grey-code rotary encoder(user inputs) need to mounted away from main pcb. 24" - 48" away. This is for space and packaging reasons. Is it OK to ...
0
votes
1answer
109 views

How exactly should I build a smart wall light switch for a smart home

I'm planning to build a smart home system and as you know smart wall light switches are a important part of it. I've been digging around for almost two weeks but still couldn't find what I'm looking ...
1
vote
1answer
163 views

AVR switch best practice

After reading a lot of posts (here and on the web), I am a bit confused. All I want to do is to get the best practice of push button connection to AVR. I have 2 "sections" to my question. the first ...
0
votes
1answer
23 views

When wiring an anlogue switch to grounded button, which goes to Y and Z?

I'm wiring an analogue switch (74HCT4066N) to throw a grounded switch. The datasheet says that the recommended Vsw value should be between GND and Vcc. This means that it's important which of Y or Z I ...
0
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0answers
40 views

Switching low-voltage AC signal from microcontroller

I have a 5V 10MHz AC line which I need to turn on/off from a microcontroller. The microcontroller will be powered by the same input signal (through rectifier). What is the best way to do that?
0
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0answers
42 views

Overriding Mechanical Switch with GPIO

I have a mechanical switch that sends a current (~5Vdc) into one of two wires. simulate this circuit – Schematic created using CircuitLab I would like to add circuitry which can override ...
1
vote
1answer
326 views

How not to waste power with digital inputs?

I am trying to make simple gates with n-MOSFETS, yet I'm not sure how to actually do physical gate inputs correctly. At first, I tried this (a single-pole, single-throw switch from +5V to gate). ...
0
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1answer
26 views

Need to control 100 Watt Pump With 15 Watt Float Switch

I am an inexperienced hobbyist So My Question may be obvious, but thank you for the help. I have a 12 V battery, which is powering two 12 V pumps. It is a 100 W pump which runs at 7 A on average ...
0
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0answers
36 views

Switching between batteries while charging

Let's say I have a 4 A current source and two 12 V car batteries, connected in series (with a tap in the middle). What in your opinion is the simplest MOSFET switching circuit, that would allow me to ...
1
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1answer
43 views

liquid level switch and solenoid valve circuit

I am trying to make sure that I have this circuit hooked up right before I actually put it to use. I’m planning to use the liquid level switch (McMaster PN:50195K93) to open the solenoid valve ...