In this toy transistor-switch model, a low input leaves the transistor in cutoff (OFF) and a high input drives it into saturation (ON), so the load behaves like an on/off branch rather than a linear amplifier.
case : transistor-switch
low input state : cutoff / OFF
high input state : saturation / ON
on-state load current : 4.80 mA
We model an NPN low-side switch with exact millivolt and microamp arithmetic. The base current comes from (Vin - Vbe,on)/Rb when the base-emitter junction is forward biased, and the collector current is the smaller of beta * Ib and the load-limited current (Vcc - Vce,sat)/Rl.
supply voltage : 5.00 V
base resistor : 10000 ohms
load resistor : 1000 ohms
transistor beta proxy : 100
low input : Vin=0.00 V -> Ib=0.00 mA, Ic=0.00 mA, Vce=5.00 V, state=cutoff / OFF
high input : Vin=5.00 V -> Ib=0.43 mA, Ic=4.80 mA, Vce=0.20 V, state=saturation / ON
high-input gain limit : 43.00 mA
high-input load limit : 4.80 mA
low input stays in cutoff : yes
high input reaches saturation : yes
switching states differ : yes
on-state current is load-limited : yes
load voltage matches resistor drop : yes