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

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1answer
20 views

Power switch with slow control signal

I am trying to switch on and off a circut that draws about 0.8 amp at 12 V. The obvious choise is to set a mosfet. The problem is that the control signal (the one that goes on the gate of the mosfet) ...
0
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1answer
38 views

Laser activated switch using a photo-transistor

I would like to make a laser activated switch using a photo-transistor or an LDR, by which I can switch off the lights in a room from a long distance. I just have to point the laser and it will detect ...
0
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1answer
37 views

Bidirectional AC Switch with IGBTs

I came across a "IGBT Bi-directional Switch" on the web while looking for a solution to my problem of protecting a TRIAC/SSR from a short-circuit. Since TRIAC/SSR turn-off is not in my control, I'm ...
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2answers
65 views

MOSFETs connected in series forming an H-bridge circuit for switching

I want to develop an H-bridge circuit using 2 MOSFET switches connected such that when the switch 1 is on (switch 2 off) the output voltage should be +5V and when the switch 2 on (switch 1 off) the ...
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1answer
34 views

Timer switch 5 min on 45 min off [closed]

i have a pump which needs to be turned on for 5 minutes and should be off for 40 minutes. Is there a specific timer relay for this function. Pls help me with the solution
1
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1answer
41 views

Switch OFF-(ON)

Easy question here. I'm designing a circuit which needs a switch for the main power supply. I would like a switch that keep the power OFF normally and the power ON while holding the push switch. Is ...
0
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2answers
29 views

Control automotive AC switch via TPS voltage

The A/C compressor is engaged via a single wire that comes from the 'A/C' button on the dash board. I want the A/C button to disengage when the throttle is at 50%. The throttle position sensor (TPS) ...
2
votes
1answer
143 views

What is the simplest analog circuit for integer addition modular 2?

This probably is a rudimentary question. I would like to have a simple analog (switch) circuit for addition modular 2, or \$a_1+a_2+\cdots +a_n \$ (mod 2). Certainly, digital transistors can ...
0
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1answer
26 views

Electrical circuit for detecting and chargine battery at 12 v

I have input source of 12 v and 6 amp. How can i use a toggle switch or a circuit that can detect if the source is active it should let the voltage pass otherwise not. Also whats the best way to ...
0
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2answers
34 views

Switch PCIe connections

I'm trying to implement a PCI express switch; one lane from SoC and, two for mini PCIe ports. Something like the picture below. But I'm confused with the Tx and Rx connections, the transmitter ...
0
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2answers
28 views

linear actuator power supply and remote or switch

this will be my first DIY project involving electricity so i want to make sure i buy the correct components. i'm purchasing a used telescoping column (aluminum and steel, 4000n) that has two actuators ...
2
votes
1answer
68 views

Device to switch a 220VAC/40A resistive load

I need to switch a 220VAC/40A resistive load. I only need on/off switching, no phase control. I would like to avoid mechanical (moving parts) components if at all possible because of reliability ...
2
votes
3answers
91 views

Switch power supply/battery

I have a power supply of 5v DC 5Ah and a 12v 2Ah lead battery. I was thinking to make a circuit to switch battery line when power is off. I made a little schema, what i'd have to put instead of switch ...
1
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1answer
99 views

Push Button ON-OFF Five seconds

I have to design a power supply with the LTC1707. It have a enable input to control it. Now I have to enable an disable this switching supply with a push button. Only when I push in button during ...
0
votes
1answer
60 views

Best way to emulate network switching on PCB

I'm interested in wiring up some Raspberry Pi Compute Modules together on a custom PCB board with DDR2 SODIMM connector interfaces. ...
2
votes
2answers
133 views

What is the difference between 4-leg and 2-leg momentary tactile switch? [duplicate]

After many search, I don't know still that what is exactly the difference between 4-leg and 2-leg momentary tactile switch? 4-leg: 2-leg: Why do they use 4-leg in many cases? for example, ...
2
votes
3answers
73 views

Is there an IC with a series of 2-input switches that can have all elements switch with one signal?

I want to select either input A's 4 signals, or input B's 4 signals. So I'm more interested in using 3-pin like switch, that can short circuit from the either A or B (not open or close one input) Is ...
0
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3answers
61 views

How should a SPDT switch be wired for a digital input?

I want to connect a switch to a digital input on a logic board and make it so that the input goes high when the switch is pressed. I'll be using a SPDT switch: Should I connect the digital input to ...
1
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1answer
65 views

How to make a simple Video Switch?

I thought making this would be simple, but I've found it a lot harder than I anticipated! What I mean is that I have one screen/monitor, and two video players (all video is through RGB component, RCA ...
0
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2answers
124 views

Transistor as switch between similar voltages

I want to use an XBee to relay data coming from a serial device. The XBee will be sleeping most of the time; waking at regular intervals, powering on the serial device, relaying the serial signals, ...
0
votes
1answer
48 views

Electronic selector / gate

The circuit that I am looking for is supposed to work as follows: The circuit has, besides power, three inputs, and two outputs. The circuit is supposed to act like a get, and let an analog signal ...
3
votes
3answers
320 views

Is a protection diode needed for a resistive load?

In some applications a flyback diode is added parallel to the load. Is that because the switching causes reverse voltage for inductive loads? What if we have a resistive load instead? Do we still need ...
2
votes
2answers
58 views

Read Switch Status without interfering with LED

I'm a software guy trying to get my head around how to measure the status of a switch connected to a LED as shown below through a digital input of a MCU. My first try was many variations of ...
0
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1answer
87 views

Two circuits with different voltages - should I use a transistor or an optocoupler as a switch

I am doing a project using the output of a Raspberry Pi GPIO pin (3.3V) to power a 12V remote control. If the two are on different circuits, can I use a transistor to switch on the 12V circuit or do ...
0
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1answer
46 views

Covering exposed contacts on a toggle switch

I need to mount a mini toggle or rocker switch to the outside surface of a box. For various reasons I cannot drill a hole, so the entire switch needs to be freestanding or glued to the surface. (There ...
0
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2answers
58 views

Alternatives to relay/contactors in DC circuits

I wanted to switch a 60Vdc line to ON/OFF using a 60Vdc controlling signal for some kind of a feedback system (yes both are 60Vdc). Presently I have two options visible: Solid State 60Vdc input ...
4
votes
3answers
447 views

Understanding a circuit for reading current passing through human bodies

I found on Instructables this circuit that is used to detect when two conductive pads are touched at the same time by a person (or, in that particular example, a chain of people). Used in ...
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2answers
91 views

How to use a 10 pin dip switch on a 8x3 Encoder (IC 74LS148)?

I've been trying to get an 8x3 encoder (IC 74LS148) working using a 10 pin dip switch, I simply connect the 1-7 ON sides of the switch as inputs for the encoder and the OFF sides of the switch to the ...
0
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1answer
62 views

7 Segment display binary to decimal

I have a few questions about 7-segment LED displays. When we build a circuit using 7 segment (common-anode) and decoder (7447), we also use 4 tactile switches to make combinations. Should I directly ...
2
votes
2answers
109 views

Better way to drive higher voltages

In order to drive pass transistors (MOSFETs) located between two non-zero voltage points, one can use a resistor divider followed by a MOSFET as seen here where V2 is high enough to drive the top ...
0
votes
1answer
37 views

Automaticaly switch on/off an (APC) UPS

I need to switch on my APC UPS at 2 AM and switch it off at 8 AM every day. Would like to switch on/off the mains power to the UPS too. I am not an electronics guy, but started to learn and have ...
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5answers
178 views

Emulating a switch with open drain outputs

I need to replace mechanical switches with some kind of digital switch. Specifically I want to sent control inputs to various arcade games that use standard JAMMA inputs, which are basically switches ...
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votes
4answers
781 views

When to use pull-down vs. pull-up resistors

After learning and experimenting with microcontrollers, the concept of pull-up- and pull-down resistors has been understood and saved to my hard drive. I now understand when and how to use them, and ...
0
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1answer
81 views

Connecting ON/OFF switch

Forgive me for the simplicity of this question but I am a microelectronics/very low voltage guy, and I have only 1 switch so I want to get it right the first time. Better safe than sorry :) I have an ...
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0answers
49 views

Rechargeable battery with a photovoltaic switch

I did some searching around on the forum but with absolutely no electrical background, I have exhausted my searching and hope I can explain my issue. What am I trying to do? I have a solar panel and ...
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1answer
73 views

replacing DIP switch with Analog Switch

In order to minimize the number of components for measuring different types of signals(Resistance, Voltage, Current, ETC), I have designed circuit using DIP switch which the user can turn on and off ...
1
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1answer
92 views

Are selected values for R1 and C1 reasonable?

Can anybody help with the circuit and specifically the selection of values for \$R_1\$ and \$C_1\$? I tried to create a p-channel based MOSFET 1A switch for MCU based upon OnSemi AND9093 Using ...
0
votes
1answer
51 views

RC Schmitt Trigger Debouncing - Cap discharged but there is a voltage across it still

As you can see in the image, I'm running the example given in here where I would debounce the limit switch. I'm running the SN7414 with the given resistors in the diagram. The problem here is that ...
0
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0answers
42 views

Mono-stable trigger circuit (monoflop) with start delay

I'm sorry if this question is a duplicate, but I'm not sure about the right terminology (in english) about my problem. I've got a device which operates at 13.5V. I want to switch this device with a ...
0
votes
3answers
106 views

Is there a type of Switch that is open until Armed?

I'm designing a circuit that will need to be off until the user decides to 'arm' the circuit. It should then always be closed (and hard to hack into the on position). Does a certain component exist ...
2
votes
2answers
85 views

How to completely turn off device when float switch is open

Background Below is the circuit I designed to open a solenoid valve after a delay from C2 (represented by L1). S1 is a float switch which closes when a resevoir goes below a given level. The reason ...
0
votes
1answer
71 views

Separated powers and high power switches? Alternatives to relais?

I want to use an Arduino (5V, 0-40 milliamps) to control some switches, which in turn control a high current line (12V, 40A). But the relays which I use use too heavy coils for the Arduino to pull ...
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votes
1answer
68 views

Switch diagram, do not know what it means, or what it represents [closed]

A neighbour asked me if I knew what these electrical switch symbols meant, or at least what they were so he could find out more:
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3answers
99 views

How to turn on/off a sub circuit with a transistor

I bought a dtc144 transistor because it was written in its datasheet that it could do a "Switching circuit" ( as it is written in the Applications section in the datasheet). I though it meant that I ...
1
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2answers
71 views

Trigger led with both Arduino and tactile button

I want to trigger a LED with both an Arduino and a hardware switch without coding any button logic in the Arduino. simulate this circuit – Schematic created using CircuitLab When the ...
0
votes
2answers
83 views

Mercury switches

Can I use a mercury contact switch for a control circuit that would normally be 240V 1.5A? If I use 480V instead? The switch has a rating for 240V. This is an electro-pneumatic switch and I can't find ...
1
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0answers
54 views

Soft latch power switch probem

I am trying to make a soft latch on-off power switch but, no matter what I do, it will not stop oscillating and will not latch at all! Can someone please help? Here is the schematic:
0
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2answers
74 views

Tippmatic auto shut-off switch - how to use it?

Some products in my company are now required to use an auto shut-off switch to be compliant with new regulations in European space (European Eco-Design Directive ErP). I got word that the device ...
0
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2answers
89 views

Push (Button) Switch Symbol

I want to know what the symbol for a button switch is. It's the kind that if you push it, the circuit is complete, and if you release it, the circuit is broken. Also, it has four prongs, two on each ...
0
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2answers
45 views

CD4053 vs IM06TS

I am in the process of finalizing a switch matrix based testing scheme. I am in need of SPDT type switching elements. Two options that I came across: CMOS Switching - CD4053 Hermitically Sealed ...