Hi Tim, I have found that driving such devices from a pic(876 in my case) port pin, while power is ~3.6V (typical battery power), will not work. For some reason the PIC cannot supply the current at this lower voltage. In one test I had to parallel 5 pins to get this to work (10mA load @ 3.5V). I now use a P channel FET (NDS0601T iirc) which seems to work a treat. Put the FET between Vdd and the power pin of the load device. Pull the gate to 0v and the device gets power. Set the gate high(~Vdd) and the power is removed from the load. John ----- Original Message ----- From: "Tim McDonough" To: Sent: Wednesday, June 05, 2002 3:38 PM Subject: [EE]: Peripheral Power Options I'm working on a project where I would like to conserve battery power by turning sensors and a radio module off when not needed. The items don't require much current, less than 10mA each. I'm interested in hearing thoughts on the following options: 1) Have the PIC control a small FET to switch device power on/off 2) Power the device directly from a port pin 3) Use a port pin to drive an inverter/buffer which powers the device The PIC will periodically be in sleep mode. Tim -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu