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Questions tagged [indicator]

The tag has no usage guidance.

2
votes
1answer
79 views

Manufacturing of Translucent LED Indicating Symbols (e.g. router indicator lights) [closed]

I've been researching how manufacturers create custom LED-illuminated symbols such as those seen on the router in the image below: I haven't been able to find any information online from custom ...
-1
votes
1answer
96 views

12V LED remains on

I am working on an automotive project where we are using an LED as an indicator for the operation of an engine cooling fan, which is turned on and off automatically by the vehicle's ECM. The module ...
12
votes
6answers
2k views

Looking for a PCB flag/indicator component

I am designing a test jig (within a 6U rack) that mates with 6 removable trays. Each tray can hold 16 sensors which can also be removed. The system will be intended to function in the following way: ...
0
votes
2answers
45 views

Logic Level Indicator Input Voltage [closed]

Here's a diagram of a logic level indicator and NAND gate. Now I'm supposed to use this in conjunction with some basic logic circuits. However I cannot find out what voltage I should have at the ...
-2
votes
1answer
78 views

Electrical panel indicator lights flickering [duplicate]

I'm wondering what the underlying mechanism of the flickering of the panel indicator lights is. Are there electronic oscillators of some kind in there?
0
votes
3answers
126 views

Battery Tester Circuit with 3 LEDS

I'm designing a small system that uses an ATMEGA328P and a LoRa module that runs on 3.3V using a AAA 1.5V battery. The battery is connected to a Boost Converter which steps up the 1.5V to 3.3V to ...
0
votes
3answers
84 views

How can I indicate that an IR LED is functioning without detecting its emissions?

I have salvaged, non-documented, IR LEDs. Without a datasheet I do not know how much current they can handle. I have run into this before: I confirm the LED is good with by viewing it through a ...
-4
votes
2answers
89 views

Red for hot, blue for cold - or vice versa?

Just wondering if there is any standard way of using LED colors to represent temperature. I have a board connected to a Peltier. When the active side (not heat sink side) is heating, I turn on a red ...
7
votes
1answer
199 views

Can I use blue-green LEDs as MCU state indicators on 3.3 V power?

Modern electronics industry has developed very efficient LEDs with nice and fancy colors (“true green” , “cyan”, and “blue”) based in InGaN technology, or similar. Some of these LEDs are specified as ...
0
votes
2answers
53 views

220 VAC Control Transformer “voltage on” indicator light.

I would like to know where to place an indicator light (what voltage, as well) for the incoming 220VAC, after the 2 pole circuit breaker? The IEC Connector will provide 220VAC to the transformer, ...
0
votes
2answers
83 views

Remotely monitor condition of fuse

I am installing five 12V batteries in a motorhome. The batteries will be wired in parallel for a 12V system and will be contained across three different enclosures. Each positive cable link between ...
0
votes
1answer
109 views

Low battery indicator doesn't work on batteries but works with trim

I made low battery indicator with LM393. But circuit doesn't work as it should. If I connect 100k trim to IN- of 1st op amp which imitate "battery voltage", op amp turns red LED on when voltage from ...
0
votes
1answer
49 views

LED indicators for 2 Positive voltages and 1 Negative

I have a seemingly simple question but I am getting stumped. I have a power supply providing +12v +5v GND and -12v. I would like to have an LED for each input voltage showing that they are working ...
0
votes
1answer
40 views

Battery level on battery indicator drops when i connect a load? [closed]

I've got this cheap battery level indicator that has 4 battery level segments, it is connected to a 12V-18AH lead acid battery that I to charge my laptop and my 1W light bulb. I really can't seem to ...
0
votes
1answer
73 views

looking for a device or tester to know if car is electrified [closed]

I'm new here and definitely not an electrical expert - so please forgive any lack of clarity and errors in my terminology or tags. We live in a rural area and drive a plug-in hybrid electric vehicle ...
0
votes
0answers
90 views

designing water level indicator using bjts (bc547 )

i am designing water level indicator using bjts (bc547 ) now i want to modify my project , when the water level get high and high the lower led should get off ,in implimentation it doesnot work , so ...
1
vote
1answer
79 views

Multiple Voltage (230VAC & 110VAC) panel indication

I am looking at driving an LED panel indicator from either 230VAC or 120VAC to inform an operator that a hazardous voltage is present. I want this indicator to operate with minimal additional ...
0
votes
1answer
679 views

Negative Voltage Supply Indicator Led

I am intending to make an indicator led circuit which shows the negative 9 V supply is coming to the circuit and led becomes on, but if there is zero volts, the led will be off. I have done this ...
7
votes
4answers
1k views

Electronic component that is like an LCD version of an LED?

Is there a liquid crystal display version of a light emitting diode? I want a visual indicator that is a small and simple 2 pin device like an LED, but instead of emitting light it just turns black or ...
1
vote
1answer
214 views

LED indication in a charger circuit

I've made this simple charger circuit and I've added a resistor and a Schottky diode at the end of the circuit (pin 2). I was wondering if I could add a LED indication so it could give me an idea of ...
0
votes
3answers
1k views

connecting a LED to a PC case fan header

On my motherboard (ASRock B150M Pro4S/D3) i have an unused 3-pin case fan header. Can i use it to drive a single LED with only a resistor in series? The fan can be configured in the BIOS to change ...
0
votes
2answers
36 views

indicator for two AC power sources

I would like to know if there is something like AND gate logic for two AC power sources i.e, if two of the sources are on the light will turn on else it will stay off .Thanks
0
votes
2answers
1k views

Relay indicator light

I feel a bit silly asking this.. I have a relay, which has a switch that turns it on/off. Next to the switch I have an indicator light which needs to turn on when the switch is turned on. I tried ...
0
votes
0answers
115 views

Low battery indicator @ 3.6V

I'm trying to make a simple low-battery indicator(3.6V 18650 LiIon) that will turn on red LED. I already tried something(schematic is below) but it doesn't work. I already have zener diodes(1/2W, 2.7V)...
0
votes
2answers
168 views

how to turn only one led (from a bi-colour led package) ON at a time by using a mosfet

I have designed a circuit to turn green led ON if the voltage from the power supply (3.3kV 10uA) is greater than 2.7kv and turn the red led ON if it is equal to or less than 2.7kV. Here 50Mohm and ...
0
votes
1answer
79 views

Getting -12v from motorcycle Indicator connection

Problem Solved, it was a silly mistake, I confused the battery positive with negative. I am making a circuit where I need input from Indicator signals . But the connection plugs for both the ...
1
vote
1answer
90 views

High Voltage Indicator based on specific threshold value

I came across an interesting problem in one of the hobby group discussions - Following problem statement describes the design requirement 1) Input voltage range can be anywhere between 0-500 Volts (It ...
0
votes
0answers
323 views

LTC3780 voltage/current limit indicator

I recently bought an LTC3780 circuit from China to build a variable power supply. I would also like to have voltage/current limit LED indicator there but every tutorial I found on the internet ...
3
votes
1answer
133 views

High voltage led detector

I need a circuit to indicate if the DC voltage across two points is exceeded a certain High value (350 V) by using LED as an indicator. For example if the voltage is 355 V then the LED will light,but ...
1
vote
2answers
495 views

BJT or MOSFET switch for led indicator problem

New to the site, and indeed fairly to electronics. I'm having a bit of trouble with this circuit I've made. It is an led indicator type circuit. The problem I'm having is that there is not enough ...
0
votes
1answer
2k views

How to connect auto cut off circuit with battery level indicator?

Guys I want to make a circuit which cut off the power automatically when the battery is full.Also,it will show the battery level. I found a circuit diagram on google and I want to build something like ...
0
votes
1answer
60 views

Detect battery/cell's charge

I am building a portable device with Raspberry Pi and powered by 3 AAA batteries in series. I am trying to create a battery indicator with a LED: Green = Full power Orange = Half power Red = Low ...
7
votes
4answers
4k views

Why a neon lamp indicator on power strip switch flickers in the dark?

Neon lamp indicators embedded in power strip switches indicate whether the switch is ON or OFF. When the neon lamp is ON in a dark environment (lights of the room are off) the lamp start to ...
0
votes
2answers
751 views

How to place “Power On” indicator lights?

I'm working on a replacement board for an old system. I have two terminal blocks. Terminal Block 1 (left) is the input from the power supply to the board. This is the primary power supply to the ...
1
vote
2answers
378 views

Led charge indicator for small supercapacitor (1F x 5.5v)

I have been playing around with a supercapacitor, 1F rated 5.5V. I charge it mostly through USB, which usually takes a couple of minutes to reach a good amount of energy. I have been thinking about a ...
3
votes
7answers
1k views

Three-way AC switch indicator without adding a wire

I am dealing with some three-way light switches that people are always forgetting to turn off. Any suggestions/schematics for making a simple LED indicator at each switch to indicate if the circuit ...
1
vote
1answer
224 views

Newbie problem with transistor switching

First post, so I hope that I adhere well to all the rules. I couldn't find any other posts that could help me, so here's my problem: I am trying to build a simple transistor switch with a 3906 PNP ...
0
votes
2answers
4k views

How to wire unusual R13-112 rocker switch

Can someone assist me in wiring this switch so the indicator and load can "light up" from 12V battery. By using terminals 1 & 2 I can power on the unit but I have no indicator light. Thanks
1
vote
1answer
529 views

How to create an on/off indicator for a SPST in a circuit?

I've recently started to work with electronics and I'm truly a beginner. Our teacher asked us to create an on/off indicator for a SPST button in a circuit. When the button is pressed the green light ...
1
vote
2answers
390 views

How to combine two LED indicators (one to VCC, one to GND)

I have two seperate sub-circuits that each have an indicator LED and only one circuit will have power at a time. So far so good, however I would much prefer to have only a single indicator light. My ...
-1
votes
3answers
128 views

source indicator, dual schottky passive load transfer switch

A dual schottky diode powers a load from either battery or off-the-shelf power supply. How to indicate which sources are providing current to the load? None, one, the other, or both. Yet draw less ...
1
vote
1answer
3k views

Fuse blown indicator circuits compilation

I have been working in a compilation of circuits to use that basically show to the user that a fuse has blown up, this is particulary useful in the bench, needless to say I haven’t tested all of them ...
0
votes
1answer
643 views

4 iPad Air charging circuit indicator led not working

I developed this circuit in order for it to be connected to 4 ipads at the same time the current they use to charge when they are on low battery goes around 1.8Amps, That its working as intended, ...
1
vote
2answers
547 views

LED monitor for solenoid

I'm trying to determine whether it is more appropriate to place an LED in series or in parallel with a solenoid. The application is to monitor the solenoid, i.e. if the solenoid is burnt out, the LED ...
1
vote
2answers
898 views

On/Off DC power indicator [duplicate]

I am pretty sure that this should be simple but the answer is eluding me. Basically I would like a simple 12V DC circuit that lights one LED (red) when a power switch to a pump is off and would ...
1
vote
1answer
705 views

Telephone “off-hook” indicator

I have a 2-line telephone that shows when a line is in-use (i.e. if an extension is picked-up, the indicator will light up on the phone). The two lines are being supplied via 1 RJ-11 cable (1 line on ...
0
votes
1answer
747 views

AC Mains Voltage Indicator Design

I am a beginner in EE and I am just studying circuits at the moment, and I have this question about designing an AC Mains Voltage indicator that indicates the voltage level of AC mains by three ...
1
vote
2answers
507 views

Need a simple circuit and IC for low voltage indicator

I have a battery operated power distribution system for some audio gear I use. I need to implement a multi-level voltage indicator via LED: Green when the voltage is above 14VDC Orange when the ...
1
vote
2answers
533 views

Any more subtle alternatives for LED's to indicate status?

Is there a low-cost, less annoying alternative to a buzzer or LED for displaying the status of an operation? I want my clock radio on at night, but it has this really annoying power indicator LED. I'd ...
2
votes
2answers
2k views

How to place an indicator light for 24 VDC Solenoid Valve?

I'm using Arduino and relay shield to control five 24 VDC Solenoid Valves. Now I want to place an indicator light (LED) for each valve, so whenever the valve is open, the light comes on. Do I need ...