Front Panel Description Figure 3-1 shows the brief description of each key on the 4285A's front panel. Figure 3-1. Front Panel Overview 1 LINE On/O Power on/o switch. In the ON position all operating voltages are applied to the instrument. In the OFF position NO operating voltages are applied to the instrument. 2 LCD Panel The Liquid Crystal Display (lcd) displays measurement results, test conditions, softkey labels, and other information. 3 SOFTKEYs Five softkeys are used to select control and parameter functions. Each softkey has a softkey label along its left side. 4 MENU Keys Menu selection keys. There are three menu keys, 4DISPLAY FORMAT5, 4MEAS SETUP5, and 4CATALOG/SYSTEM5. The menu keys are used to access the corresponding selection of instrument functions. 3-2 Overview 5 CURSOR Keys The CURSOR arrow keys are used to move the eld select cursor from eld to eld on the LCD display page. When the cursor is moved to a eld the eld changes to an inverse video image of the original eld. The cursor can only be moved to a eld, it can't be moved into a monitor area. 6 ENTRY Keys The ENTRY keys are used to enter numeric data into the 4285A. The ENTRY keys are composed of the digits 405 to 495, a period 4.5, a minus sign 4-5, 4ENTER5, and 4BACK SPACE5 keys. 4ENTER5 terminates numeric input data and enters the displayed value on the Input line (second line from the bottom of the LCD screen). 4BACK SPACE5 deletes one last character of the input value. 7 GPIB Status Indicator The GPIB status indicators consist of the RMT (remote), TLK (talk), LTN (listen), and SRQ (service request) indicators. These indicators are used to show the 4285's GPIB status when it is interfaced to a controller via GPIB. 8 4LCL5 9 4TRIGGER5 Key The Local (LCL) key returns the 4285A to local (front-panel) operation from the remote (computer controlled) operation state unless a Local Lockout command has been invoked from the computer. 4LCL5 is the only front-panel key activated while the 4285A is in the REMOTE state. Key This key is used to manually trigger the 4285A when it is set to the Manual Trigger mode. A MEMORY Card Slot and UNLOCK Button The MEMORY card slot is where you insert the memory cards. The UNLOCK button is used to eject a memory card. B 4DC BIAS5 Key 4DC BIAS5 is used to enable or to disable the DC bias output. 4DC BIAS5 is a toggle type switch, and the DC BIAS ON/OFF LED indicator is located above 4DC BIAS5. There are two ways to apply the DC bias to the DUT. One is Option 001 DC bias option and the other is the 42841A Bias Current Source combined with the 42842C Bias Current Test Fixture. Either one can be selected in the CONFIG eld. 4DC BIAS5 simply the DC bias output turns ON or OFF, and the DC bias value must be set in the BIAS eld. C CONTRAST Control Knob This knob is used to adjust the LCD's CONTRAST. Overview 3-3 D UNKNOWN Terminals These are the UNKNOWN terminals used to connect a four-terminal pair test xture or test leads for measuring the DUT.Available four terminal-pair test xtures or test leads are refer to the Accessories Selection Guide For Impedance Measurements (Catalog number 5963-6834E). INSTALLATION CATEGORY I E FRAME Terminal This Terminal is tied to the instrument's chassis and can be used for measurements that require guarding. 3-4 Overview Rear Panel Description Figure 3-2 gives a brief description of the 4285A's rear panel. Figure 3-2. Rear Panel Overview 1 GPIB Interface Connector The GPIB interface connector allows interfacing with a controller and other GPIB instruments. 2 Interface Connectors When interface options are installed, the interface connectors will be installed as shown in Figure 3-2. When the 4285A is not equipped with an interface option, blank covers are installed. 3 INT DC BIAS MONITOR Connector This BNC connector is used for monitoring the DC bias voltage or current applied to the DUT. The monitor function can be switched to either voltage ( V BIAS ) or current ( I BIAS ) on the MON eld in the MEAS SETUP page. This connector is installed only when Option 001 is installed. NNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNN 4 EXT TRIGGER Connector The 4285A is triggered by inputting a TTL active low to high going edge trigger pulse. Overview 3-5 5 LINE Input Receptacle AC power cord receptacle. 6 LINE Fuse Holder Fuse holder for the 4285A's line fuse. Refer to Figure 2-3 to determine the correct line fuse rating. 7 LINE VOLTAGE SELECTOR The switch used to match the 4285A to the AC operating voltage being used. Refer to \Line Voltage Selection" in Chapter 2 to determine the correct operating voltage. 3-6 Overview