The Tektronix Type CA is the most common plug-in for 500-series scopes – over 50,000 were produced. It was designed by John Kobbe and Bill Polits. The NORMAL/INVERT switch and algebraic add functions were suggested by Charlie Rhodes.

Tektronix Type CA
24 MHz dual-channel amplifier
Type CA front view

Compatible with 500-series scopes

Produced from 1959 to 1973


Type CA is an enhancement over its predecessor, Type 53/54C, adding ADDED mode to the A, B, CHOPPED, ALT repertoire. The "A" in "CA" stands not only for the fact that it is a modified, enhanced replacement, but also because the feature added was "ADDED".

Type CA was introduced in 1959 and discontinued in 1973, making it not only the most-produced but also one of the longest-lived.

Late versions have BNC connectors instead of UHF connectors.

Lavoie Laboratories produced an unauthorized clone, the Lavoie LA-265-CA.

Key Specifications

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The risetime of a Type 545 oscilloscope with a Type CA plug-in is 15 nanoseconds, and the bandwidth is 24 MHz. Maximum vertical sensitivity is 50 mV/div.


Documents Referencing CA

Document Class Title Authors Year Links
IBM 223-6725-2.pdf Application Note Tektronix oscilloscopes (IBM Customer Engineering Manual) 1960



Some Parts Used in the CA

Part Part Number(s) Class Description Used in
6AK5 154-0014-00 154-0206-00 154-0084-00 Vacuum Tube (Pentode) RF pentode B C CA G K L ML S Z 517 517A 524
6AU6 154-0022-00 157-0073-00 157-0059-00 154-0284-00 Vacuum Tube (Pentode) RF pentode 107 160 181 190 60 2A60 72 3A72 3C66 310 310A 316 317 360 502 502A 506 511 511A 512 513 516 517 517A 524 526 529 RM529 531 531A 535 536 545 545A 546 547 549 555 561 561A 561S 564 565 567 570 575 581 581A 585 585A 80 C CA Q