Keithley 485

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Keithley 485
Digital picoamperemeter
Keithley 485 front

Produced from (?) to (?)

Manuals
Manuals – Specifications – Links – Pictures

The Keithley 485 Picoamperemeter is a dedicated picoamperemeter from the mid-1980s, from the same generation and model series as the better-known Keithley 197 "Microvolt DMM".

The 485 operates as a feedback (transimpedance) amperemeter (i.e. the input burden is constantly low at less than 0.2 mV), has a resolution of 4½ digits (19999), some rudimentary built-in logging capabilities, as well as an optional GPIB interface.

This instrument measures only (low) currents, in seven decadic ranges from 2 nA to 2 mA full scale. In the 2 nA range, the least significant digit resolves 100 fA (0.1 pA).

Key Specifications

Current 7 decade ranges, 2 nA to 2 mA full scale
Display 4½ digits, LCD

please expand

See also

Internals

The (optional) GPIB interface communicates with the base instrument over an opto-isolated serial port. It uses a separate 6805 CPU.

Pictures

Components

Some Parts Used in the Keithley 485

Part Part Number(s) Class Description Used in
Motorola 6800 156-0426-00 156-2413-00 156-5472-01 Monolithic integrated circuit 8-bit microprocessor 021-0206-00 021-0374-00 067-0902-00 067-1137-99 222 222A 222PS 2424L 2445 2465 2467 4051 7250 7912 7912AD 7A16P 7A29P 7B81P 7B90P 833 834 835 836 CG5001 CG551AP CG5010 CG5011 DF1 DF2 DM5010 FG5010 MI5010 SI5010 PS5004 PS5010 SG5010 Keithley 181 Keithley 182 Keithley 175 Keithley 175A Keithley 191 Keithley 192 Keithley 195 Keithley 195A Keithley 197 Keithley 220 Keithley 224 Keithley 230 Keithley 263 Keithley 485 Keithley 580 Keithley 617
Motorola 6820 156-0427-00 Monolithic integrated circuit "Peripheral Interface Adapter (PIA)" 021-0206-00 7A16P 7B81P 7B90P Keithley 175A Keithley 197 Keithley 485 Keithley 580
NEC μPD7225 Monolithic integrated circuit LCD driver Keithley 175A Keithley 197 Keithley 485 Keithley 580