Questions tagged [normally-open]

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How to make an ON/OFF circuit to light up an LED, using only relays and one normally open button? [closed]

I'm new in this world. I tried latching relays. I only achieved keeping the LED ON but I'm not able to turn it off with the same button. Any idea?
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Breaker with alarm

I am thinking about a theft alarm for an HVAC condenser. The condenser is installed outside and subject to burglary. I think a viable approach is detecting when it is detached from power. The HVAC ...
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Reverse NO limit switch signal

I am working on set a limit switch for safety function while moving a hoist. Due to the restriction of mechanical design, I can only choose the ball plunger limit switch (BP4SWA) which is Normally ...
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Converting Normally Closed to Normally Open

I have a truck that has a different engine swapped into it. I'm trying to get the cruise control to work and I've tracked the issue down to the Set/Coast switch. The PCM is expecting a 12 V signal ...
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What is the Umlaut Symbol in this relay?

I'm wondering if the reoccurring "Umlaut" (Ö) symbol in a manual for a process controller that I'm referencing is an actual electronic representation of something, if so what, or if this process ...
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"Normally closed" switch: does it use more power than a "Normally open" for a low-power battery-powered ATtiny project?

I have a "normally closed" magnetic door sensor, that I'd like to use with an ATtiny microcontroller. Does a "normally closed" switch use more power than a "normally open" switch? i.e. since the ...
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6 votes
3 answers
2k views

Normally Closed Optoisolators

I understand that typical optoisolators can logically be considered as "normally open". However I have a situation where I'd like the circuit controlled by the opto to be normally closed, mainly for ...
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1 answer
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How to wire a normally open switch to a recoil start engine with no external battery?

I am making an engine toggle switch for a recoil-start engine using two switches wired in series for safety. The engine will shut off only when two "kill" cables on the front have been connected. In ...
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2 votes
2 answers
532 views

how to convert a PWM AC dimmer circuit from normally-closed to a normally-open one?

Hi, As you see in schematic, the circuit is a normally-closed AC dimmer. Therefore when the connection between microcontroller - which produce pwm - and mosfet get halted, the lamp will be always on ...
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changeover normally closed to normally open

I have a switch that is used for setting tool lengths on CNC Mill. The switch operates normally closed, and breaks the signal when a tool touches it, which sets the length via a macro. The control ...
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Liquid level switch with normally open contact

If something is described as a "liquid level switch", and contains a normally open contactor, would this imply that a dry sensor would cause the contactor to open, and a submerged sensor would cause ...
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