chapter 4 bipolar junction transistors

If lc is 50 times larger than Ib, then Bdc is (a) 0.02 (b) 100 (c) 50 (a) 0.02 (b) 100 50 (d) 500

c. 50

If the output of a transistor amplifier is 5 V rms and the input is 100 mV rms, the voltage gain is (a) 5 (b) 500 (c) 50 (d) 100

c. 50

A DMM measuring on open transistor junction shows (а) 0 V (b) 0.7 V (c) A DMM measuring on open transistor junction shows (а) 0 V (b) 0.7 V (c) OL A DMM measuring on open transistor junction shows (d) Vcc (а) 0 V (b) 0.7 V (c) OL

c. OL

When a lowercase r' is used in relation to a transistor, it refers to (a) a low resistance (c) an internal ac resistance (b) a wire resistance (d) a source resistance

c. an internal ac resistance

In saturation, VCE is (а) 0.7 V (b) equal to Vcc (c) minimum (d) maximum

c. minimum

In a phototransistor, base current is (a) set by a bias voltage (b) directly proportional to light intensity (c) inversely proportional to light intensity (d) not a factor

b. directly proportional to light intensity

The emitter current is always (a) greater than the base current (b) less than the collector current (c) greater than the collector current d) answers (a) and (c)

d) answers (a) and (c)

the three terminals of a bipolar junction transistor are called a. pnp b. npn c. input output ground d. base emitter collector

d. base emitter collector

An optocoupler usually consists of (a) two LEDS (b) an LED and photodiode (c) an LED and a phototransistor (d) both (b) and (c)

d. both (b) and (c)

In cutoff, VCE is (а) 0 V (b) minimum (c) maximum (d) equal to Vcc (e) answers (a) and (b) (f) answers (c) and (d)

f. answers c and d

For operation as an amplifier, the base of an npn transistor must be (a) positive with respect to the emitter (b) negative with respect to the emitter (c) positive with respect to the collector (d) 0 V

(a) positive with respect to the emitter

To saturate a BJT, (a) IB= Ic(sat) (b) Is > Ic(sat)/BDC (c) VCc must be at least 10 V (d) the emitter must be grounded

(b) Is > Ic(sat)/BDC

The bias condition for a transistor to be used as a linear amplifier is called A forward-reverse (b) forward-forward (c) reverse-reverse (d) collector bias

A forward-reverse

Once in saturation, a further increase in base current will (a) cause the collector current to increase (6) not affect the collector current (c) cause the collector current to decrease (d) turn the transistor off

b. not affect the collector current

When operated in cutoff and saturation, the transistor acts like a (a) linear amplifier (b)switch (c) variable capacitor (d) variable resistor

b. switch

In a transistor amplifier, if the base-emitter junction is open, the collector voltage is (a)Vcc (c) floating (b) 0V (d) 0.2 V

a. Vcc

The Bdc of a transistor is its (a) current gain (b) voltage gain (c) power gain (d) internal resistance

a. current gain

The approximate voltage across the forward-biased base-emitter junction of a silicon BJT is (а) 0 V (b) The approximate voltage across the forward-biased base-emitter junction of a silicon BJT is (а) 0 V 0.7 V (e) 0,3 V (d) VBB

b. 0.7

In a given transistor amplifier, Rc = 2.2 ko and r = 20 o, the voltage gain is (а) 2.2 (b) 110 (c) 20 (d) 44

b. 110