beautypg.com

Static measurements – Elenco AM/FM Radio Kit User Manual

Page 44

background image

-43-

STATIC MEASUREMENTS

Figure 38

Figure 37

Connect your VOM to the circuit as shown in Figure 38.
Turn the power ON. The voltage at the emitter of Q6
should be about 0.7 volts. Record the voltage here:

V(Q6) = ________.

Turn the power OFF. If your answer is greater than 2
volts, check R20, R21, R22, R24, Q6 and the battery.

Since the current through resistor R22 is equal to the
current through transistor Q6, calculate the current
through Q6 as follows:

Current (I) = V(Q6) / R22

Your calculated answer should be between 0.0005
amps (0.5 milliamps) and 0.0011 amps (1.1
milliamps).

Current (I) = __________.

Connect your VOM as shown in Figure 37. Switch the
AM/FM switch to the FM position. Set your VOM to
read 9 volts DC. Turn the power ON. The voltage at

this point should be between 7 and 9 volts. Turn the
power OFF. If you do not get this reading, check R25,
C24 and the battery voltage.

FM VOLTAGE

TRANSISTOR CURRENT TEST

GND

TP15

Battery

GND

TP15