Questions tagged [voltage-detector]

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1answer
48 views

Open drain voltage detector NCP301LSN45T1G

I have to use a voltage detector to detect a decrease in voltage to reset a microcontroller. I have found the NCP301LSN45T1G to do this. But I have a question about the Reset Output current (N-...
0
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1answer
63 views

Voltage tester pens

This is my first post here so please have patience with me: I understand, there are at least two kinds: a direct contact tester which basically is a neonnlight, and a resistor a non contact AC meter ...
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1answer
96 views

How do I make a discrete voltage detector?

I would like to design a circuit which has outputs LOW when the voltage it is connected to is below a threshold, like 3.3V. There are some ic's you can buy to do this, but I would like to make my ...
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1answer
228 views

How do non contact voltage detectors work on open circuits

I’ve seen how people use non contact voltage detectors to check whether or not a socket’s live wire has power. Non contact voltage detectors take advantage of capacitive coupling that occurs in AC in ...
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2answers
313 views

Why does a non contact AC voltage detector detect voltage on a DC line that is not flowing

I have two non contact voltage detectors (Klein and Greenlee) ..both are rated to detect AC voltage with a sensitivity range from 50 to 1000 V. I used these detectors on 9 different cell phone power ...
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2answers
485 views

Flip a Schmitt-Trigger when current flows through a Zener diode

I am trying to design a circuit using an intermitent power source (a bicycle hub generator), which is rectified and filtered, and regulated at 6,8V. Now I want to "detect" when the power source is ON ...
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2answers
296 views

Non contact (contactless) AC or DC detection?

I'd like to detect AC or DC current (not the current level just nothing or something => ON/OFF) in a wire with a (DIY) sensor just in contact (glued) with the wire plastic insulator. At the end the ...
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2answers
392 views

24 VAC Detection Using Optocoupler

I have been using an HCPL3700 to detect 24VAC, but they are large and relatively expensive. I have tested the design shown in the figure (AC input to the diode, and measuring output collector-emitter ...
1
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1answer
330 views

Detecting power loss in a microcontroller to save context

I am trying to detect sudden power loss in my micro controller to save its state before the MCU dies. I have been thinking to utilize one of my GPIO pin to detect the supply voltage and use a large ...
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2answers
64 views

detection of dc pulse

following is a pulse which i obtained from a circuit and i want to get a count when the pulse is initiated. My circuit is to detect a lightning and i obtain this pulse in our high voltage laboratory ...
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0answers
40 views

Measuring direction of a three phase motor (400VAC, 50 Hz) within a 5V-circuit

I've got a lot of motor controller boards, without the actual motor, and I'm interested in measuring at the output terminals (U,V, W) to see if there's any voltage. This to just check rudimentally if ...
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3answers
85 views

How to find status (on/off) of any applicance ( light, fan, etc.) connected to an electrical circuit

There are 4 appliances connected to an electric circuit, how to determine which applicance is on/off and pass that information to an electronic device in binary form. The idea is to make an ...
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1answer
2k views

Detect Sound From Google Chromecast Audio

Recently I have brought a Google Chromecast Audio and the audio signal is fed directly to my stereo. I want to detect on the sound level in order to turn the stereo on and off. Then I successfully ...
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0answers
57 views

Controlling NMOS

Can I control a NMOS (don't look the reference in the schematic) to shutdown a LDO with a voltage detector like so ? Or is there missing something? simulate this circuit – Schematic created ...
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5answers
144 views

Simple, low power way to buffer a 500mV threshold signal to an open collector output?

I have a signal that is 0-500mV when low and 600-900mV when high. I'd like to buffer this signal to an open collector output. The output must withstand a maximum of 3.3V be capable of sinking 60uA. ...
0
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1answer
368 views

Will this circuit suffice for low battery detection for any microcontroller?

I'm making a major digital circuit powered by two 3.6 volt cordless phone NiCD rechargeable batteries, and one thing I want to include is a low battery detector. To protect the rest of the circuit ...
2
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1answer
245 views

Detecting presence of a voltage without drawing too much current

I am working on a microcontroller project for a garage door opener. Rather than supply additional magnet+reed switches or other kind of detectors for sensing whether the door is full-open or full-...
2
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2answers
478 views

Separating Phase and Neutral in AC?

I need determine if a cable is connected to a wall-socket (230V) on the other end with a timer in-between. 230VAC---TIMER---CABLE Depending on how the timer is ...
2
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2answers
1k views

Efficient method for isolated detection of AC voltage without a stepdown transformer

What is an efficient method to detect the presence of Line AC power in an isolated method? My first thought would be to use an optocoupler, but in order to do that, you need to supply the current ...
3
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1answer
136 views

Why can't a control unit detect this 12 volt signal while my multimeter can?

I work as a contractor installing stop request signs on busses. The stop request sign is basically a device that illuminates when a rider pulls the stop cord. When it is pulled, 12v is sent to the ...
0
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1answer
126 views

How to detect a signal if it is greater than VDD or smaller than 0?

I need to detect a signal if it is greater than VDD or smaller than 0. I can't use comparator because the input signal is outside of common-mode input range and I have only one power supply VDD. Is ...
2
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1answer
123 views

Detecting when AVR ICSP header has a cable connected

I have a bunch of Atmega16A MCUs laying around so I want to use them with an ESP8266 to relay temperature and such in each room of my home to a server. The thing is, if I need to update the firmware ...
0
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1answer
125 views

Is there anyway to detect lowest voltage of a signal like capacitor and diode do for the high one?

Is there any simple (not the best one) way to detect the lowest value of a signal, like a diode and capacitor detect the peak value, I want to do it for detect the lowest value of a signal.
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2answers
606 views

HDMI 5 port switch detecting LED with Arduino

Hey all I am wanting to make a project for this HDMI 5 port switch I have. I want to be able, with an Arduino, to detect which of the 5 ports are being used (only 1 can be used at any given time). ...
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2answers
589 views

Can a logic level converter be used as a replacement for a relay for detecting if a buzzer is currently active?

I have a small microcontroller (VoCore, runs Linux, has wifi and GPIOs) and i want to use it to hook into another system (basically a doorbell) to make the state of the doorbell-buzzer available over ...
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2answers
395 views

Digital Voltmeter - TriColor LED Output

I'm very new to electronics and I wanted to start with something that would hopefully simple, but also useful. I'd like to make a circuit that can read a DC input voltage (between 9V and 20V) and ...
3
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2answers
357 views

Diode detector strange discharging

I am building a diode detector circuit in order to detect ASK signal with 125 KHz carrier frequency and 8 KHz data rate. However, I realized I would say a strange behaviour and discharging of ...
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1answer
1k views

Detect alternating current using one contact only and arduino analog input

I am trying to setup an arduino so it can detect an AC where it only has access to one pole. (kind of like these "electricians screwdrivers" that you put in one of the connections of an electric ...
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4answers
527 views

Sensitive audio detector

Here's the link to the project I'm currently working on: http://www.allaboutcircuits.com/vol_6/chpt_4/5.html. I have a question about this transformer. I haven't been able to find an audio ...
7
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3answers
5k views

Why are non-contact voltage detectors sensitive to vibration?

I have noticed that if I slap a non-contact voltage detector against my palm, the LED blinks. I have tried this with four six different detectors, each a different brand, and each clearly a different ...