A 5 V DC source is connected through resistor R₁ = 1 kΩ to a node X. From node X to the source’s negative terminal there are two parallel paths: resistor R₂ = 3.3 kΩ, and a silicon diode with its anode at X. Use the constant-drop model with 0.7 V. Find the diode current ID in mA.
A 9.1 V Zener diode is fed from 20 V through a 220 Ω resistor, with no load connected. Find the current IR in the resistor.
An NPN transistor with β = 200 is biased by a base resistor RB = 820 kΩ from the supply VCC = 9 V. The collector resistor is RC = 1.5 kΩ and the emitter is grounded. Take VBE = 0.7 V and assume the transistor is in the active region. Find the collector–emitter voltage VCE.
An NPN transistor with β = 120 is biased by a base resistor RB = 560 kΩ from the supply VCC = 15 V. The collector resistor is RC = 470 Ω and the emitter is grounded. Take VBE = 0.7 V and assume the transistor is in the active region. Find the collector current IC in mA.
A diode is modelled as 0.65 V in series with 25 Ω (it conducts above 0.65 V). It is in series with a 220 Ω resistor across a 12 V supply. Find the operating current ID where the diode line meets the load line.
A 5.1 V Zener regulator must supply up to 25 mA to a load. The input can drop to 18 V, and the Zener needs at least 2 mA to regulate. Find the largest series resistance Rmax that keeps it regulating.
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