Switch Selection The circuit of Fig. 1-13a has two switches. Switch S₁ is on and connects the voltage source (V = 24 V) to the current source (I = 2

A). It is desired to open switch S₁ to dis- connect V from the current source. This requires that a second switch S₂ close to provide a path for current I, as in Fig. 1-13b. At a later time, S₁ must reclose and S₂ must open to restore the circuit to its original condition. The cycle is to repeat at a frequency of 200 kHz. Determine the type of device required for each switch and the maximum voltage and cur- rent requirements of each. Vs + V1 (a) Io + (b) ↑iz Switch Selection The circuit of Fig. 1-13a has two switches. Switch S₁ is on and connects the voltage source (V = 24 V) to the current source (I = 2 A). It is desired to open switch S₁ to dis- connect V from the current source. This requires that a second switch S₂ close to provide a path for current I, as in Fig. 1-13b. At a later time, S₁ must reclose and S₂ must open to restore the circuit to its original condition. The cycle is to repeat at a frequency of 200 kHz. Determine the type of device required for each switch and the maximum voltage and cur- rent requirements of each. 1-1. The current source in Example 1-1 is reversed so that positive current is upward. The current source is to be connected to the voltage source by alternately closing S₁ and S₂. Draw a circuit that has a MOSFET and a diode to accomplish this switching. Vs 2 Vs + Vs-V₁=8 Off (c) cloud V₁ Anode ļia Cathode (a) V2 V2 • diz $₂ diz 个)。 ↑ Case I: si closed: 1,= 10, V₁=0 V 9 open: |√√√₁₂=√₁ ||. || 52: Í₂: =0 Core I: S₁ open: 1₁=0, V₁ = _ Vs → S₁: Diode: 9 ر Sz: closed: 12 = To √₂=0 | Si open (-V5₂0) (S₂) S₂: moshet: cloved iz clore (0,13) open (VS, 0) 1-2. Simulate the circuit in Example 1-1 using PSpice. Use the voltage-controlled switch Sbreak for S₁ and the diode Dbreak for S₂. (a) Edit the PSpice models to idealize the circuit by using RON = 0.001 № for the switch and n = 0.001 for the diode. Display the voltage across the current source in Probe. (b) Use RON = 0.12 in Sbreak and n = 1 (the default value) for the diode. How do the results of parts a and b differ? Vcs Vs I