This Dev log is pulled straight from my notes while working on the project

Goals
- understand how to read an NPN transistor datasheet

Reading NPN Transistor Data sheets
- VCE(sat): when the transistor is in saturation mode and is acting as a switch there is a measured drop in voltage from collector to emitter which is rated as VCE(sat)
- NPN transistors are current driven devices so the primary information and concern is current related
- Ic = Ib x hFE
- Icex = collector current cutoff: leakage current through the collector to emitter when the device is off
- hFE(includes leakeage) = hfe(small signal current gain)
- hFE(Current gain) varies with Ic(collector current)
- Vbe(on) = Base-Emitter on voltage: Voltage at which current begins to flow and the collector starts to draw current
- Saturation mode: using the transistor as a switch
- minimum voltage between the collector and the emitter is called Collector-Emitter Saturation voltage (Vce(sat)) often 0.2v to 0.3v
- Ic at maximum: the transistor can not put anymore current through it
- Vce at minimum: the voltage drop between collector and emitter is at a minimum
- The current at the collector is not responding to a change in the base current
- Power dissipation
- Pd = Ir x Vr
- power dissipated across a resistor is equal to the current through the resistor times the voltage across the resistor
- Pd(total) = Pd(C) + Pd(B)
- there is power being dissipated through both the base and the collector in a BJT
- Pd(actual) < 0.5 x Pd(datasheet)
- actual power dissipation must be half the rated value for safety rating
- Ic = Max Collector Current: maximum current that you should have running through the device
- Ic(actual) < (2/3) x Ic(datasheet)
- actual current should be 2/3 or less of rated value for safety rating
- Maximum Voltage rating for safety ratings
- V(actual) < (2/3) x V(datasheet)
- Past the saturation region is the active region where any increase in Ib doesn't increase Ic
- In the active region the Ic stays the same over a long Vce range
- IE. Past a certain voltage (Vce(sat)) the Transistor doesn't care what voltage is across Vce as the Ic stays the same for that Ib
- General rule of them is that base current should be 1/10 the collector current

Updated Design
- Using A gate driver instead of a NPN for the MOSFET and using a dual Channel MOSFET IC
- PD chip that can manage up to 20V 5A