Converting Alternating Current To Direct Current; Half Wave Rectifier Single Diode; Full Wave Rectifier Bridge Rectifier; Components - Tecumseh ECV100 - 120 Technician's Handbook

CONVERTING ALTERNATING CURRENT TO
DIRECT CURRENT
In order to charge a battery, it is necessary to convert
alternating current (A.C.) to direct current (D.C.). This is
accomplished by using a diode or rectifier (diag. 3). A single
diode makes use of only one half of the A.C. signal and is
known as HALF WAVE RECTIFICATION (diag. 4). This is
acceptable in certain applications. In certain situations it
is necessary to make use of the entire A.C. signal. To
accomplish this, multiple diodes in a bridge configuration
are used to produce FULL WAVE RECTIFICATION (diag.
5).
Current flows through a diode when the anode is more positive than the cathode. The cathode end of the diode should
point toward the battery when diode is used between a charging system and a battery.

HALF WAVE RECTIFIER SINGLE DIODE

The single diode allows only the positive half of the A.C. signal through. It does not allow the negative portion through.
+ VOLTAGE
- VOLTAGE
FULL WAVE RECTIFIER (BRIDGE
RECTIFIER)
The full wave rectifier makes use of the entire A.C. signal,
converting it to D.C.

COMPONENTS

BATTERY

The batteries used in conjunction with Tecumseh engines
are 12 volt lead acid or "maintenance free" style. The
chemical energy produced by the dissimilar metals of the
battery plates provides a electrical potential that is used to
power the electric starter or unit accessories. Consult the
original equipment manufacturer's service manual for battery
size, capacities, and testing procedure.

WIRING

The wires used in Tecumseh electrical systems are copper stranded with an insulated coating around the copper strands.
CONDITION: All wiring must be fully insulated between connection points, securely fastened and free of foreign material
(such as rust and corrosion) at the connection points. This is especially important in the use of batteries where much of
the potential may be lost due to loose connections or corrosion. Remember to check the insulation on the wire. All it
takes is a pin hole to "ground out" on the engine or frame. This is of special concern when moisture or water is present.
This may cause the engine to run erratically or be impossible to start.
HALF WAVE RECTIFIER
(SINGLE DIODE)
A.C. INPUT
ANODE
DIRECTION OR FLOW OF CURRENT
+ VOLTAGE
- VOLTAGE
FULL WAVE RECTIFIER
(BRIDGE RECTIFIER)
+ VOLTAGE
- VOLTAGE
A.C. INPUT
A.C. INPUT
+ VOLTAGE
D.C. OUTPUT
- VOLTAGE
CATHODE
BAND OR OTHER
MARKING INDICATES
CATHODE END
Ý
D.C. OUTPUT
+ VOLTAGE
(D.C.)
3
4
5
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