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Low power consumption on/of switch

Topic last updated 20 May 2011, by Robert Spilleboudt. 3 replies
Serge Sozonoff
20 May 2011

Hi All,

Not being an electronics expert what is the recommended way to build a GPIO triggered on/off switch so that I can power off certain sensors in my system? Sensor current draw will not exceed 100mA @ 9.5V

Obviously the switch circuit itself should consume as little current as possible.

I guess a FET, Transistor or relay are all options just not sure which will draw the least current?

Kind thanks, Serge

Martin Smith
20 May 2011

Your best bet is probably a simple NPN transistor. A relay will consume a holding current and an N-channel MOSFET might need too high a gate voltage to be used by the mbed.

Serge Sozonoff
20 May 2011

Thanks,

So maybe something like http://www.nxp.com/documents/data_sheet/BC817_BC817W_BC337.pdf ?

Serge

Robert Spilleboudt
20 May 2011

Look at
http://digital-diy.com/General-Electronics/digi-tip-logic-level-fets-n-channel.html
http://digital-diy.com/handy-tips/67-digi-tip-logic-level-fets-p-channel.html

I use such a P-channel as electronic switch.

Robert