Light source efficiency math?

Started by mike in sci.electronics.design5 days ago 31 replies
LED

I started with the basic question. If I have a LED source that produces 100 lumens/watt bolted to an infinite heat sink, how much power does...

I started with the basic question. If I have a LED source that produces 100 lumens/watt bolted to an infinite heat sink, how much power does the heat sink have to carry away? Googling got me a million comparisons of leds and incandescent for home lighting. Poking around the Cree site didn't help either. The only relevant (marketing) statement I found was that an incandescent produces 9...


scope diffamp

Started by John Larkin in sci.electronics.design5 days ago 5 replies

https://www.ee-quipment.com/products/differential-preamplifier Looks cool; we'll try one. The old Tek plugin scopes had nice diffamp...

https://www.ee-quipment.com/products/differential-preamplifier Looks cool; we'll try one. The old Tek plugin scopes had nice diffamp modules, but no more. This is nice, fully isolated, but expensive: https://www.tek.com/datasheet/ada400a-differential-preamplifier-datasheet And this one: https://www.mouser.com/ProductDetail/Tektronix/TIVH08L/?qs=%2fha2pyFaduiSR%252bjhrLu0HTWsnav...


OT: Reducing gun violence in the US

Started by Anonymous in sci.electronics.design5 days ago 8 replies

Today's issue of the Proceedings of the (US) Academy of Science has a comment...

Today's issue of the Proceedings of the (US) Academy of Science has a comment paper http://www.pnas.org/content/114/46/12097.extract.html?etoc and a full paper http://www.pnas.org/content/114/46/12162.full Cooling off periods for buying hand-guns apparently reduce gun deaths buy about 17% in the state that have introduced them, and they wouldn't inconvenience a well-regulated militia, ...


Windows USB question

Started by John Larkin in sci.electronics.design5 days ago 17 replies

Some times we want to use a USB port, often through an FTDI serial converter chip, to talk to a device or to a test set. Under Windows, the...

Some times we want to use a USB port, often through an FTDI serial converter chip, to talk to a device or to a test set. Under Windows, the COMn port seems to come up with random n. Sometimes we write a program to scan all the comm ports, looking for our target device. That can be messy. Does anyone know of a way to reserve or nail a USB com port? Apparently that is not a problem wi...


Test (ignore)

Started by Bill Bowden in sci.electronics.design6 days ago

Test from astroweb.

Test from astroweb.


OT: Excess output "picture" clutter from Excel

Started by Robert Baer in sci.electronics.design6 days ago 21 replies

This is a multi-part message in MIME format. --------------080407080708070703090300 Content-Type: text/plain; charset=ISO-8859-1;...

This is a multi-part message in MIME format. --------------080407080708070703090300 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Offending Excel instruction shown: vNam = Cells(2, 7).Text + "V" 'board voltage pPath = "G:\ANALOG\HVREG\Boards\TITANTWO\CodatronD\" 'ActiveSheet.Shapes(1).Select 'Application.ActivePrinter...


One photo is worth?

Started by Michael A Terrell in sci.electronics.design6 days ago 10 replies


EMC - RF IMMUNITY

Started by Anonymous in sci.electronics.design6 days ago 5 replies

Hello everyone. 1.) I have an electronics board that has 10 wires coming out that gets connected to an end users board with an Ethernet type...

Hello everyone. 1.) I have an electronics board that has 10 wires coming out that gets connected to an end users board with an Ethernet type cable. During our Electromagnetic Compatibility (EMC) Testing for the RF Immunity Testing there is a disturbance of our system around 100-120 MHz and 1 GHz –2.7 GHz. (Some of the values returned from the Analog to Digital converter o


IC of amplifier in EMCO probe kit?

Started by Joerg in sci.electronics.design6 days ago 9 replies

Does anyone know what IC they use in the amplifier of this probe kit? The P/N of the amp is 7405-907B and goes to...

Does anyone know what IC they use in the amplifier of this probe kit? The P/N of the amp is 7405-907B and goes to 3GHz. http://www.bellnw.com/media/images/products/ETS/7405.jpg It is a simple TO-92 metal can, four pins, IN, OUT, V+ and GND. Needless to say there is no lettering on it, bare metal. Just the supply, no inductor like with MMIC. Cap in, cap out, that's it. This amp is used ...


Weird I-V

Started by George Herold in sci.electronics.design6 days ago 6 replies

I'm trying to understand this I-V curve (see Ascii art below.)* the sample is a piece of n-type Si (I don't know doping density.. lightly...

I'm trying to understand this I-V curve (see Ascii art below.)* the sample is a piece of n-type Si (I don't know doping density.. lightly doped.) There are Ti/Au contacts (made into a Hall bar, A stripe of current input on each end and four voltage probe points along the length (3mm x 6mm maybe)) This is just the I-V across the large current contacts. ...


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