A 9 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 = 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 5.1 V Zener diode is fed from 9 V through a 150 Ω resistor, with no load connected. Find the current IR in the resistor.
An NPN transistor with β = 80 has voltage-divider bias from VCC = 18 V: R₁ = 39 kΩ from VCC to the base and R₂ = 15 kΩ from the base to ground. The collector resistor is RC = 2.7 kΩ and the emitter resistor is RE = 1.5 kΩ. Take VBE = 0.7 V and use the Thévenin equivalent of the divider (do not neglect the base current). Find the collector current IC in mA.
An NPN transistor with β = 200 has voltage-divider bias from VCC = 18 V: R₁ = 56 kΩ from VCC to the base and R₂ = 8.2 kΩ from the base to ground. The collector resistor is RC = 5.6 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 current IC in mA.
An NPN transistor with β = 80 switches a 1 kΩ load resistor connected between VCC = 9 V and its collector. The emitter is grounded. The base is driven from a 3.3 V logic output through a base resistor RB. Take VBE = 0.7 V and VCE(sat) = 0.2 V. Find the largest base resistor RB, in kΩ, that still drives the transistor just into saturation.
An NPN transistor with β = 100 switches a 470 Ω load resistor connected between VCC = 9 V and its collector. The emitter is grounded. The base is driven from a 3.3 V logic output through a base resistor RB. Take VBE = 0.7 V and VCE(sat) = 0.2 V. Find the largest base resistor RB, in kΩ, that still drives the transistor just into saturation.
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