A 12 V DC source is connected through resistor R₁ = 330 Ω to a node X. From node X to the source’s negative terminal there are two parallel paths: resistor R₂ = 10 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 V DC source is connected through resistor R₁ = 1.5 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.
An NPN transistor with β = 80 has voltage-divider bias from VCC = 12 V: R₁ = 56 kΩ from VCC to the base and R₂ = 22 kΩ from the base to ground. The collector resistor is RC = 1 kΩ and the emitter resistor is RE = 1 kΩ. Take VBE = 0.7 V and use the Thévenin equivalent of the divider (do not neglect the base current). Find the collector–emitter voltage VCE.
An NPN transistor with β = 50 is biased by a base resistor RB = 680 kΩ from the supply VCC = 9 V. The collector resistor is RC = 3.3 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.
A 3.3 V Zener regulator must supply up to 20 mA to a load. The input can drop to 9 V, and the Zener needs at least 5 mA to regulate. Find the largest series resistance Rmax that keeps it regulating.
A 12 V Zener regulator must supply up to 30 mA to a load. The input can drop to 24 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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