Backup Battery Circuit
The CPU board is supplied with backup power from the on-board battery, BT1, whenever the line voltage
is off or too low to supply the instrument with the required input voltage. Transistor Q1 is turned on by
the +15 V supply to 5 V to the circuits connected to the battery with a minimum drop in voltage.
While the instrument is turned on, CR2 keeps the battery from being back charged.
A4 Test Points
The test points in Table 4-3 can be checked for the correct signals on the A4 CPU board:
Test Point
Description
TP1
System Clock. 12MHz
TP2
Read/Write signal from U13
TP3
5 V Common
TP4
+5 V
TP5
Reset Signal from U17
TP6
Real Time Clock (U1) Output. Used for Calibration
TP7
Interrupt Request Signal from U1
TP8
Battery Voltage
TP9
15 V Common
TP10
+15 V
Table 4-3. A4 Test Points
Theory of Operation
Manual No. 20790, Rev C, November 1998
4-11
Содержание 8501A
Страница 12: ...Series 8500A Peak Power Meters x Manual No 20790 Rev C November 1998 ...
Страница 16: ...Series 8500A Peak Power Meters xiv Manual No 20790 Rev C November 1998 ...
Страница 18: ...Series 8500A Peak Power Meters xvi Manual No 20790 Rev C November 1998 ...
Страница 74: ...Series 8500A Peak Power Meters 2 48 Manual No 20790 Rev C November 1998 ...
Страница 156: ...Series 8500A Peak Power Meters 4 30 Manual No 20790 Rev C November 1998 ...
Страница 165: ...Figure 5 3 Model 8501A 8502A Calibration Components Testing and Calibration Manual No 20790 Rev C November 1998 5 9 ...
Страница 180: ...Series 8500A Peak Power Meters 5 24 Manual No 20790 Rev C November 1998 ...
Страница 230: ...Series 8500A Peak Power Meters 8 2 Manual No 20790 Rev C November 1998 ...
Страница 236: ...Series 8500A Peak Power Meters A 6 Manual No 20790 Rev C November 1998 ...
Страница 247: ...Figure D 2 Pre Amplifier Line Driver Schematic RF Detectors Manual No 20790 Rev C November 1998 D 5 ...
Страница 262: ...Series 8500A Peak Power Meters Index 8 Manual No 20790 Rev C November 1998 ...