43 4-57.   In a positive-diode counter that provides accurate counting, what is the only variable allowed in the input signal? 1.  Pulse width 2.  Pulse duration 3.  Pulse amplitude 4.  Pulse-repetition frequency Figure 4G.—Basic frequency counter. IN ANSWERING QUESTIONS 4-58 THROUGH 4-60, REFER TO FIGURE 4G. 4-58.   An input signal to the counter will cause (a) what capacitor to charge through R1 and D2 and (b) what capacitor to discharge through D1? 1.    (a) C1 (b) C1 2.    (a) C1 (b) C2 3.    (a) C2 (b) C1 4.    (a) C2 (b) C2 4-59.   What components produce the smooth dc output-voltage level? 1.  C1, D1, and R1 2.  C1, D2, and R1 3.  C1, C2, and R1 4.  C2, C3, and R2 4-60.   When the input frequency is increased, what is the effect on (a) the input interval, (b) the number of pulses per given time and (c) the dc output voltage? 1.  (a) Longer (b) less (c) higher 2.  (a) Longer (b) more     (c) lower 3.  (a) Shorter (b) less (c) higher 4.  (a) Shorter (b) more     (c) higher Figure 4H.—Step-counter frequency divider. IN ANSWERING QUESTIONS 4-61 AND 4-62, REFER TO FIGURE 4H. 4-61.   An output pulse will occur when the charge on C2 1.  builds a magnetic field in the base winding 2.  drops below the cutoff-bias level of Q1 3.  exceeds the bias level of Q1 4.  reaches the source potential of the voltage applied 4-62.   What component develops the bias for Q1? 1. R1 2. R2 3. C2 4. T1