On / off switch must be connected in

As we know, current flows through the live wire, but to stop the current to flow or to allow the current to flow, we need to make sure that we can start or stop the flow according to our circuit need. As we know, current flows only if the circuit is complete. A switch is place in the path of live wire which can act as circuit maker or breaker.

Table of Contents • • • • • • • • • • • • Why switch and fuse must be connected in the phase line only? The fuse wire is always connected in the live wire of the circuit because if the fuse is put in the neutral wire, then due to excessive flow of current when the fuse burns, current stops flowing in the circuit, but the appliance remains connected to the high potential point of the supply through the live wire. The L2 terminals of both the switches are connected to one terminal of the light bulb, while the other terminal of the light bulb is connected to the neutral of the AC power supply….Standard 2 Way Switch Wiring. Switch 1 COM (connected to) Switch 2 COM (connected to) Status of Light L1 L2 ON L2 L1 ON L2 L2 OFF Why it is unsafe to connect the fuse in the neutral wire? If the fault is on the neutral wire between the lamp and the fuse provided in it, the fuse will burn off because the neutral wire is at slightly higher potential w.r.t earth and thus the fault current will flow through the neutral wire and the fuse wire blows out. Why do we connect fuse to the phase wire? That is the main phase line. Also, a fuse should completely isolate the load or wiring from the supply by its burn off or on removal. If the circuit has any other conduction path, the complete current still has to flows through the fuse. Thus, a fuse connected in phase can provide all over protection. What will happen if a switch is connected to a neutral wire? If switch is connected in the neutral wi...

Two capacitors C 1 ​ and C 2 ​ (where C 1 ​ > C 2 ​ ) are charged to the same initial potential difference. The charged capacitors are removed from the battery and their plates are connected as shown in the Fig 4 . 9 ( a ). The switches S 1 ​ and S 2 ​ are then closed, as shown in the Fig 4 . 9 ( b ).

The requirements of Art. 404 apply to all types of switches including snap (toggle) switches, dimmer switches, fan switches, knife switches, circuit breakers, occupancy sensors, and automatic switches, such as time clocks and timers [Sec. 401.1] ( Fig. 1). Switch connections When wiring 3-way or 4-way switches, only the phase conductors can be switched [Sec. 404.2(A) and (B)]. As a conductor for switching purposes (switch leg), you can use a permanently reidentified white conductor within a cable [Sec. 200.7(C)(1)]. Switches controlling line-to-neutral lighting loads must have a neutral conductor installed at all switches serving bathroom areas, hallways, stairways, and habitable rooms or occupiable spaces as defined in the building code [Sec. 404.2(C)]. Where 3-way and 4-way switches are visible in a room, only one of the switches requires a neutral conductor. You don’t have to install a neutral conductor at lighting switch locations under any of the following conditions: (1) Where conductors enter the box enclosing the switch through a raceway with enough cross-sectional area to accommodate a neutral conductor. (2) Where the box enclosing a switch can be accessed to add or replace a cable without damaging the building finish. (3) Where snap switches with integral enclosures comply with Sec. 300.15(E). (4) Where the lighting is controlled by automatic means. (5) Where switches control receptacles. A neutral conductor must be installed for any replacement switch that requi...

• SECTIONS • Electrical Fundamentals • Electrical Inspections • Industry Standards • Electrical Safety • Evolving Technologies • Industry News • COLUMNS • Perspectives on PV • UL Solutions Question Corner • NFPA Code Talk • Canadian Perspectives • Beyond the Service Point • Certification Insights • Code Hunter • Video Library • MAGAZINE • Latest Articles • Magazine Archive • Subscribe • Author List • Contribute • Advertise • Reprint Permissions • Privacy Statement • Terms and Conditions • CODE ADOPTION • IAEI.ORG Question: What has a couple of poles and says “NO” when turned upside down? Answer:A single-pole switch! Weren’t we all taught as apprentice electricians and helpers that if you install a single-pole switch upside down, rather than say “ON” it will say “NO” to you! We perhaps take switches for granted. Receptacle outlets are the “face” of electrical devices, and luminaires are often grand and elegant in design and attract lots of attention. Switches on the other hand, are often over-looked unless something is not working. When you flip a switch to the “ON” position and the luminaire does not illuminate, what’s the first thing you do? The first thing we check is the light bulb. If the light bulb is OK, we might even check the connections to the luminaire while we’re up on the ladder. If the connections are OK, it must be a loose wire in the receptacle outlet just ahead of the switch in the branch circuit. Only after we check all possible failure points do we even c...

I was wondering if it is possible to wire an on/off switch into the cable of a wall-wart USB power charger as easily as it is to wire an on/off switch into a regular power cable? Or are there precautions that should be taken into consideration before attempting to do such a thing. I've seen extension cables with these switches on them so I know it is possible but they seem too expensive for what seems like an easy job to do yourself. Attached is a picture of the charger which I'd like to do this to. Thanks \$\begingroup\$ A switch in the cable won't help. The power supply will still be using power even when your switch is off. To stop it using power, you must separate it from the mains - which you can only do with a switch in the power supply (forget it) or between the plug and the mains. That's with an extension cord with switch or a plug with switch that you plug into the outlet. Or just unplug then damn thing when you are not using it. \$\endgroup\$ Yes, you can do what you're describing as long as the power adapter is regulated 5V and at least 500mA. Since you are starting with an adapter for USB already, you don't need to worry about that. You'll want to break the Hot part of the AC line before the transformer and using a switch that is rated for the proper AC loading and wattage. 5V at 1A at the output will be 5W power rating and I'd assume high inefficiencies for cheap chargers so at least a 20W switch just to be on the safe side. Follow standard safety precautions ...

We saw previously, that the N-channel, Enhancement-mode MOSFET (e-MOSFET) operates using a positive input voltage and has an extremely high input resistance (almost infinite) making it possible to use the MOSFET as a switch when interfaced with nearly any logic gate or driver capable of producing a positive output. We also saw that due to this very high input (Gate) resistance we can safely parallel together many different MOSFETS until we achieve the current handling capacity that we required. While connecting together various MOSFETS in parallel may enable us to switch high currents or high voltage loads, doing so becomes expensive and impractical in both components and circuit board space. To overcome this problem Power Field Effect Transistors or Power FET’s where developed.V We now know that there are two main differences between field effect transistors, depletion-mode only for JFET’s and both enhancement-mode and depletion-mode for MOSFETs. In this tutorial we will look at using the Enhancement-mode MOSFET as a Switch as these transistors require a positive gate voltage to turn “ON” and a zero voltage to turn “OFF” making them easily understood as switches and also easy to interface with logic gates. The operation of the enhancement-mode MOSFET, or e-MOSFET, can best be described using its I-V characteristics curves shown below. When the input voltage, ( V IN ) to the gate of the transistor is zero, the MOSFET conducts virtually no current and the output voltage ( V...

Switches don’t require any fancy equations to evaluate. All they do is select between an open circuit and a short circuit. Simple. But how could we live without buttons and switches!? What good is a blinky circuit with no user input? Or a deadly robot with no kill switch? What would our world be without with big red buttons you should Covered in This Tutorial • Momentary vs. Maintained Switches • What do SPST, SPDT, DPDT, etc. all mean? • The difference between normally closed and normally open buttons • Lots of pretty button pictures • Important switch ratings • Switch applications Suggested Reading Before diving into this tutorial, make sure you’re up to snuff on the most basic of electronics knowledge. If you’re not familiar with the following concepts, consider reading their tutorials first. Then come back, and we’ll have some fun button talk. • • • • • Looking to explore different switches? What is a Switch? A switch is a component which controls the open-ness or closed-ness of an electric circuit. They allow control over current flow in a circuit (without having to actually get in there and manually cut or splice the wires). Switches are critical components in any circuit which requires user interaction or control. A switch can only exist in one of two states: open or closed. In the off state, a switch looks like an open gap in the circuit. This, in effect, looks like an open circuit, preventing current from flowing. In the on state, a switch acts just like a piece o...