A 15 V DC source is connected through resistor R₁ = 470 Ω to a node X. From node X to the source’s negative terminal there are two parallel paths: resistor R₂ = 4.7 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 6.2 V Zener diode is fed from 20 V through a 330 Ω resistor, with no load connected. Find the current IR in the resistor.
An NPN transistor with β = 50 is biased by a base resistor RB = 470 kΩ from the supply VCC = 9 V. The collector resistor is RC = 2.7 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 = 820 kΩ from the supply VCC = 10 V. The collector resistor is RC = 1 kΩ 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.
An NPN transistor with β = 200 switches a 220 Ω load resistor connected between VCC = 5 V and its collector. The emitter is grounded. The base is driven from a 5 V logic output through a base resistor RB. Take VBE = 0.7 V and VCE(sat) = 0.2 V. For reliable switching, design for a base current 4 times the minimum needed for saturation. Find RB in kΩ.
An NPN transistor with β = 80 switches a 680 Ω load resistor connected between VCC = 12 V and its collector. The emitter is grounded. The base is driven from a 5 V logic output through a base resistor RB. Take VBE = 0.7 V and VCE(sat) = 0.2 V. For reliable switching, design for a base current 5 times the minimum needed for saturation. Find RB in kΩ.
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