Radio Shack 22-218 Owner's Manual page 36

Notes:
• When you measure the resistance of a component in a
circuit, disconnect one side of the component you are
testing. This prevents other components in the circuit
from interfering with the reading.
• When you try to identify cathode and anode ends or the
type of transistor (PNP or NPN), the actual polarity of the
meter's voltage is the opposite of the polarity suggested
by the test probes' color. The red test probe is the nega-
tive source, and the black test probe is positive.
36