3 to 50VDC LED Indicator (How)? Why--> Power-Over-Etherne

Very simple project actually, Power-Over-Ethernet Injector similar to this type of device https://www.hyperlinktech.com/web/ps4820-poe.php

The idea behind the Giraffe design is to use two Griaffes to add Power-Over-Ethernet to devices like Access Points that don't support POE.

I was thinking of using a LM317 as a current regulator for an LED but the max voltage is 37V and the POE standard is 48V (although most home non POE gear is far less than that often 5V to 15VDC)

egads ... don't use a linear reg, you'll need a huge heatsink to get 2-3 amps at 3.3v off a 48v line

look at www.national.com and www.fairchild.com and www.ti.com for "point of load" or even "poe" buck converters

many of them are pre-programmed for common voltages (3.3, 5, 12, 15) and require only a few caps and a small coil.

Re: 3 to 50VDC LED Indicator (How)? Why--> Power-Over-Eth

William At MyBlueRoom said:

I was thinking of using a LM317 as a current regulator for an LED but the max voltage is 37V and the POE standard is 48V (although most home non POE gear is far less than that often 5V to 15VDC)

Click to expand...

Try using a current regulating diode. They are the size of a 1N4148 or TO-92 and good for a few mA from 2~3V up to about 100V.

Try using a current regulating diode.

Click to expand...

Awesome, I've been working with electronics for more than 30yrs although my purview is digital and I've never heard of a constant current diode till now.

Found an excellent description here

:mrgreen: eblc1388 your oracle status is truly deserved