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1answer
52 views

How would you go about creating a lux meter for very low light (0.0001 to 1 lux)?

I like to take pictures of the the sky in really dark places like Death Valley. To get an estimate of exposure times for the foreground I would like to measure the light intensity. According to ...
1
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2answers
72 views

Serial Data Input through Microcontroller to Output Voltage

I am new here and new to programming, so I thought maybe some of you might be able to help me in the right direction. I am looking to design a circuit that receives serial data from an RS232 port on ...
-4
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1answer
73 views

Smart meters and filtering [closed]

My mother suffers from Electromagnetic hypersensitivity and her electricity provider recently installed her a HF Smart Meter (CERM 1). I've been researching about ways of filtering the dirty power ...
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2answers
93 views

Can I use Mic to input Frequency Meter circuit?

Í'm new to application level of electronics that I'm studying.I have a project to do in college and I was thinking to do a Frequency Meter circuit that can measure the frequency of given input signal ...
1
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1answer
183 views

How can I detect brain waves

I want to build some type of electrical circuit to detect alpha, beta , theta etc. waves from the brain and maybe even show the frequency in hertz . Or at first, generate a higher power wave for my ...
0
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1answer
182 views

Frequency Selective Voltmeters

Does anyone here know of any cheap-ish handheld meters that are capable of measuring the voltage at specific audio frequencies? I'm dealing with a few constant frequency signals on the same wire - ...
2
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2answers
97 views

Is there any such thing as a linear panel meter?

I like to use regular panel meters for showing data. I would like to know if there's such a thing as a linear meter, say 10 cm long or so. By linear I mean that the indicator moves up some scale in a ...
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votes
1answer
93 views

Voltage/resistors/series/impedance/meter

Assume you measure a power supply voltage through a series 1M OHM resistor and observe that is drops by 1/2 its former value when no resistor is in series. What is the input impedance of the meter? ...
1
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3answers
354 views

How do I hijack a reading from the circuit of my digital meter

I have a tri - meter (ph, ppm, temp) that reads and displays readings on three LCD screens. I'm trying to hijack the measurement at some point in the circuit and read it in through on of the inputs on ...
1
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3answers
410 views

How to light an LED when a voltage hits a certain point

Lets say I need an LED to indicate when a DC voltage reaches 5 volts or more. I don't want the LED to be dim when it is at 4.5 or anything. I just want it to be full bright at 5, 0 bright at anything ...