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

crooper · 04-05-2007, 03:11 PM

I know this is an old thread, but I'm trying to get it to work so I don't have to listen to my hard drive spool up.

The ampctrl service works great, DTR voltage swings -11.2v to +11.2v from off to on, and the signal will switch on ONE of my 3 amps. I have an automotive relay switching +12v to my amp REM inputs -- works great but DTR can't power it. I tried an 800 mA NPN transistor to switch the relay but it doesn't work. I measured the resistance across the emitter/collector as well as the output voltage with the service on and off and they don't change.

Does anybody have this kind of setup (with the transistor) or just a good explanation sans electronics skematics? I'm not an EE, they make no sense to me.

04-05-2007, 03:11 PM	#99
crooper Variable Bitrate Join Date: Nov 2006 Posts: 410	I know this is an old thread, but I'm trying to get it to work so I don't have to listen to my hard drive spool up. The ampctrl service works great, DTR voltage swings -11.2v to +11.2v from off to on, and the signal will switch on ONE of my 3 amps. I have an automotive relay switching +12v to my amp REM inputs -- works great but DTR can't power it. I tried an 800 mA NPN transistor to switch the relay but it doesn't work. I measured the resistance across the emitter/collector as well as the output voltage with the service on and off and they don't change. Does anybody have this kind of setup (with the transistor) or just a good explanation sans electronics skematics? I'm not an EE, they make no sense to me.