The 0.2V is the "Collector-Emitter Saturation Voltage", also labeled "Vce(sat)". The is the voltage across the collector-emitter junction when the transistor is in saturation...which is what you want for a transistor used as a switch.yes thats what I meant because it saturates like I remembered above, correct?
in other words it's an npn so the Vce has a low positive minimum voltage.
Where in the spec sheet do you find the 0.2 V (what term is used?)
I'm an engineering math major not EE
And, just so you know, there are two ways to operate the bipolar transistor: 1) small signal mode (which this is not) and 2) saturation/switch mode (which this is). The standard NPN uses a gain of 10 when calculating for saturation mode. This is in the datasheet where the specs are. There will be an example or two, right there in the spec data referring to Ib and Ic (base current and collector current), and when you do the simple calculation you'll see that the gain is 10.
And you normally calculate "backwards". That is, you start with the collector current, a gain of 10, and calculate the base resistor to achieve that.
Statistics: Posted by Mike**K — Mon Jun 09, 2025 12:44 am