Bridge Rectifier, Bipolar Junction Transistors

1. Determine the peak output voltage for the bridge rectifier in Figure 1 shown. Assuming the practical model, what PIV rating is required for the diodes? The transformer is specified to have a 12 Vrms secondary voltage for the standard 120 V across the primary.

1. In the full-wave center-tapped rectifier circuit, the transformer has a turns ratio of 1:2. The transformer primary winding is connected across an AC source of 230V (rms), 50 Hz. The load resistor is 50?. For this circuit, determine the DC output voltage, peak-to-peak ripple in the output voltage, and output ripple frequency. Show all work.
2. In an NPN transistor, the emitter and collector are both N-type materials.
   1. True
   2. False
3. The dc beta is defined as the dc collector current divided by the dc emitter current.
   1. True
   2. False
4. When the ground side of each voltage source is connected to the emitter of a bipolar junction transistor, it is called a common collector.
   1. True
   2. False
5. The middle region of a transistor is the ________.
6. A transistor has a collector current of 12 mA and a base current of 40 µA. What is the current gain of the transistor? Show all work.
7. A transistor has a current gain of 260. If the base current is 90 µA, what is the collector current?

1. Assume the input signal to a rectifier circuit has a peak value of V_m = 12 V and is at a frequency of 60 Hz. Assume the output load resistance is R = 2kΩ and the ripple voltage is to be limited to V_r= 0.4 V. Determine the capacitance required to yield this specification for a (a) full-wave rectifier and (b) half-wave rectifier. Show all work.

Given Vm=12V

f = 60Hz

   R = 2k?

         Vr = 0.4V

2.  A full-wave rectifier is to be designed to produce a peak output voltage of 12 V, deliver 120 mA to the load, and produce an output with a ripple of not more than 5 percent. An input line voltage of 120 V (rms), 60 Hz is available. Consider a bridge type rectifier. Specify the transformer ratio and the size of the required filter capacitor. Show all work.

3. Silicon diodes are used in a two-diode full-wave rectifier circuit to supply a load with 12 volts D.C. Assuming ideal diodes and that the load resistance is 12 ohms, compute the secondary transformer voltage, the load ripple voltage, and the efficiency of the rectifier. Show all work.

4. A half-wave rectifier using silicon diode has a secondary emf of 14.14 V (rms) with a resistance of 0.2 Ω. The diode has a forward resistance of 0.05 Ω and a threshold voltage of 0.7 V. If load resistance is 10 Ω, determine the following:

o    dc load current

o    dc load voltage

o    voltage regulation

o    circuit efficiency

o    diode PIV and current rating