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3.5mm jack max power input (warning this is not possible!)
Posted: Wed Apr 08, 2015 8:02 am
by T0BY
Hello!
Does anyone know the maximum power/current/voltage I can put into the 3.5mm jack on my B+ without damaging it? I am using it as an input to monitor a variable external high voltage output.
Many thanks,
Toby
Re: 3.5mm jack max power input
Posted: Wed Apr 08, 2015 8:18 am
by rurwin
You can't put any power into the 3.5mm jack.
The 3.5mm jack is an output only. It outputs stereo audio and composite video. There is no audio, or any other analogue, input on the Raspberry Pi. It always needs an external ADC converter.
Re: 3.5mm jack max power input
Posted: Wed Apr 08, 2015 8:21 am
by davidcoton
Er, unless I've missed something, the 3.5mm jack is the audio/video output. Don't put anything into it!
In any case input current and hence power are functions of the input, not the source. The only thing to worry about is voltage. In general Pi (digital) inputs are 3.3v maximum, but there is no built-in analogue input.
Re: 3.5mm jack max power input
Posted: Wed Apr 08, 2015 8:21 am
by fruitoftheloom
T0BY wrote:Hello!
Does anyone know the maximum power/current/voltage I can put into the 3.5mm jack on my B+ without damaging it? I am using it as an input to monitor a variable external high voltage output.
Many thanks,
Toby
ROFL
http://www.raspberrypi-spy.co.uk/2014/0 ... video-jack
Re: 3.5mm jack max power input
Posted: Thu Apr 09, 2015 6:37 pm
by T0BY
The only non-invasive current detector I can find has a 3.5mm jack on it so I wondered if I monitored the voltage across the port whether I could pick up the information in this way. Is there voltage monitoring on the 3.5mm port?
Re: 3.5mm jack max power input
Posted: Thu Apr 09, 2015 6:41 pm
by DougieLawson
The 3.5mm is audio OUTPUT only (on an A or B) and audio/video OUTPUT only (on an A+,B+ or 2B) you can't use it for ANY form of input or voltage sensing.
Re: 3.5mm jack max power input
Posted: Thu Apr 09, 2015 7:09 pm
by mikronauts
NO
T0BY wrote:The only non-invasive current detector I can find has a 3.5mm jack on it so I wondered if I monitored the voltage across the port whether I could pick up the information in this way. Is there voltage monitoring on the 3.5mm port?
Re: 3.5mm jack max power input
Posted: Thu Apr 09, 2015 7:38 pm
by Bruny
T0BY wrote:The only non-invasive current detector I can find has a 3.5mm jack on it so I wondered if I monitored the voltage across the port whether I could pick up the information in this way. Is there voltage monitoring on the 3.5mm port?
maybe they should use 6.35mm to avoid confusion?
Re: 3.5mm jack max power input
Posted: Thu Apr 09, 2015 7:48 pm
by T0BY
Thanks for your help. I'll need to think again.