Fluke 76 - Display

Theory of Operation
Circuit Descriptions 2
2-11
power supply decoupling for the shunt and series regulators, respectively. Q10 provides
base drive for Q3 at turn on. Voltage level information is presented in Table 2-1
Display 2-22.
The liquid-crystal display (LCD) operates under control of the microcomputer. Segments
are driven by the computer and displayed on the LCD. Both digital readings and an
analog bar-graph display are presented in conjunction with annunciators and decimal
points. Refer to the Fluke 76 User Manual for information about the display.
Table 2-1. Typical Voltage Levels and Tolerance (Referred to Common)
Voltage Level Tolerance
VDD 3.0 ± 0.2
VSS -3.2 ± 0.2
VBT- -6.1 (battery at full 9V charge)
-3.2 (battery at low charge of 6.5V)
REFH 1.23 ± 0.04
PS0 1.23 ± 0.15
PS1 0 ± 0.15
VOA 2.2 to 1.7 (referenced from VSS)
VOB 1.07 to .85(referenced from VSS)