Section 6A
Power Supply
POWER SUPPLY BLOCK DIAGRAM 6A-1.
Refer to the Power Supply Block Diagram, Figure 6A-1, to identify the major
functional sections and for help in following the power and current paths of the power
supply.
POWER SUPPLY CIRCUIT DESCRIPTION 6A-2.
The instrument power supply provides all the DC and AC power requirements of the
system. The DC supplies are provided to all circuitry of the system and to the DC fan.
The AC power is used for filament heat for the front panel display.
Line power passes through the line filter and fuse. The filter also provides switching for
the various power line voltages, from which the instrument is designed to operate. The
AC power is then routed to the power transformer primary winding. The transformer
includes an additional safety device, which serves as a thermal shutoff to break the
primary AC supply in case the transformer exceeds a safe operating temperature.
To accommodate the various line voltages, the case of the line fused receptacle/filter of
the 6080A/AN contains a line voltage selector card that can be plugged in two different
ways. Plugging the line voltage selector card into one of its two positions allows
selecting the line voltage of 115 or 230V AC.
The secondary windings of the transformer are connected to a linear DC power supply
assembly that provides the instrument with the supplies shown in Table 6A-1.
NOTE
The front panel power switch does not break the AC line power or the
transformer secondary. The power supply and some other parts of the
instrument, such as the display assembly, are powered while the line plug
is energized.
In the standby mode (power switch is off) the active supplies are the 23.4V and the
display filament lines. In addition, various parts of the power supply assembly are
energized, such as all transformer secondary windings, rectifiers, and filter capacitors.
The bridge rectifiers in the power supply are used in either a bridge or full-wave
center-tapped configuration with capacitor input filters. Figure 6A-1 shows the
rectifier configurations as well as the component designations for the various supplies.
6A-1
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