Regulator Diagram (Prestolite) - Piper Navajo PA-31 Service Manual

1241
R ALTERNATOR
SWITCH
Figure 11-32. Regulator Diagram (Prestolite)
b. Rectifier Diode: The rectifier diode will pass current in one direction only (forward
direction); and in this respect, it may be compared to a one-way check valve.
c. Zener Diode: The Zener diode, in addition to passing current in the forward
direction, will pass current in the reverse direction only when a particular value of voltage is
applied in the reverse direction. It is this Zener action which makes it adaptable for use as a
voltage sensing device in the regulator.
d. Resistor: The resistor is a device which is used to limit current flow.
11-43. REGULATOR COMPONENTS (LAMAR). Alternator output voltage can, within
limits of the design capability of the alternator, be controlled by properly varying the
average level of current flow in the rotor winding. The LAMAR solid state electronic
regulator is well suited for this purpose. The alternator, due to its design, has self-limiting
current characteristics and therefore needs no current-limiting element in the regulator.
a. Transistor: The transistor (Symbol "Q") is an electronic device which can control
the flow of current in an electric circuit. It has no mechanical or moving parts to wear out.
b. Rectifier Diode: The rectifier diode (Symbol "D") will pass current in only one
direction (forward direction); and in this respect it may be compared to a check valve.
c. Zener Diode: The zener diode (Symbol "Z") in addition to passing current in the
forward direction, will also pass current in the reverse direction when a particular value of
reverse voltage is applied. This property makes it useful as a voltage reference device in the
regulator.
d. Capacitor: The capacitor (Symbol "C") is a device which will store electrical energy
for short periods of time. This property makes it useful as a filter element to smooth
variations of voltage.
e. Resistor: The resistor (Symbol "R") is a device which is used to limit current flow.
Reissued: 10/12/79
ELECTRICAL SYSTEM
11-43
PIPER NAVAJO SERVICE MANUAL
4C5