A 5 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 = 1.5 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 blue LED with a forward voltage of 3.2 V runs from a 5 V supply through a series resistor. Find the resistance R that sets the LED current to 10 mA.
An NPN transistor with β = 120 has voltage-divider bias from VCC = 20 V: R₁ = 82 kΩ from VCC to the base and R₂ = 8.2 kΩ from the base to ground. The collector resistor is RC = 2.7 kΩ and the emitter resistor is RE = 470 Ω. 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.
3 green LEDs (forward voltage 2.2 V each) are connected in series with a resistor to a 9 V supply. Find the resistance R that sets the current to 25 mA.
A 5.6 V Zener regulator has a 100 Ω series resistor. The input can rise to 22 V, and the load may be disconnected. Find the largest power PZ,max the Zener must dissipate.
A 5.1 V Zener regulator has a 100 Ω series resistor. The input can rise to 15 V, and the load may be disconnected. Find the largest power PZ,max the Zener must dissipate.
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