Darkside

I see. so basically I need to just add say a 1K resistor in series to the 47ohm and then cross Base to the Emitter with another 1K and that should be fine. sounds ok to me. I am going to use it to turn on PC with the 2222. I may even use a 4n25 opto to isolate the motherboard from the circuit just incase.

I know you can use a resistor to limit the current but if you mean for a specific reason then no. and The resistor to ground to turn off the Transistor? not sure. sorry for my noobish line of questions. I know alot of basics but some stuff is new to me like using mosfets.

I will likely going to use it as a general toggle. Like say use a MPS2222 Transistor to make act as a simple connection for a PC Reset button. nothing major I was just using the Relay as a example. I am just wanting to make a simple touch switch that will operate at 5v. I can and have made a 12v touch switch using a LM555 timer IC which worked GREAT at 12v but had issues at 5V.

So. If I understand correct if I wanted to hook this up to a Relay I would connect the pos lead to the Source and the Sink to the Ground of the Relay coil? I am still kinda confused on it.

I dont follow this schematic. I have looked and looked and its just not popping. I dont know what its refering to for "Source" and "Sink". the PDF can be found at http://www.web-ee.com/Schematics/Doorknob_Alarm/5vmom1.pdf If anyone can shed some light on this please I have all the parts just I do not want to start until I know what that Source and Sink are for. Thanks.