MP3Car.com - View Single Post - Windows Service that raises DTR on powerup

awh4992 · 01-09-2004, 07:47 AM

[quote=GingerPrince]You could also use it to power a relay to turn your neons on/off

[/QUOTE

that would hafta be a pretty small relay as the serial port DTR and RTS lines only supply ~10mA, which is barely enough to power a chip or 2, let alone an electromagnet in the relay. a better way would be to just use a transistor that can switch the amount of current ur neons use. the transistor only sucks nano to microamps through its base, so it's suited better for driving loads as opposed to sucking current from an output on the serial port chip. you would be using an npn transistor since the DTR pin is negative until the OS tells the serial chip to bring it to about +8 or +9v. a relatively simple circuit to build, providing you can get your hands on a transistor that won't blow up when u have ur neons connected directly to it.

01-09-2004, 07:47 AM	#11
awh4992 Newbie Join Date: Jan 2004 Vehicle: 1989 Ford Bronco II Posts: 52 My Photos: ()	[quote=GingerPrince]You could also use it to power a relay to turn your neons on/off [/QUOTE that would hafta be a pretty small relay as the serial port DTR and RTS lines only supply ~10mA, which is barely enough to power a chip or 2, let alone an electromagnet in the relay. a better way would be to just use a transistor that can switch the amount of current ur neons use. the transistor only sucks nano to microamps through its base, so it's suited better for driving loads as opposed to sucking current from an output on the serial port chip. you would be using an npn transistor since the DTR pin is negative until the OS tells the serial chip to bring it to about +8 or +9v. a relatively simple circuit to build, providing you can get your hands on a transistor that won't blow up when u have ur neons connected directly to it.