I need to drive a relay from my Arduino, and I have the following design,
Here is the 2N5210 (NPN) Data Sheet http://www.fairchildsemi.com/ds/2N/2N5210.pdf.
According to the data sheet, I should expect the following,
hFE = 250; IC = 10mA, VCE = 5.0V
VCE(sat) = 0.7V; IC = 10mA, IB = 1.0mA
VBE(on) = 0.85V; IC = 1.0mA, VCD = 5.0V
Given all that, and the fact that the relay coil is 208 Ohms, I’m expecting the following:
IB = 2mA
ICE = 20mA
Am I even close? I plan on building a bunch of these over the weekend, so any advice would be much appreciated.