1A2: Difference between revisions

From TekWiki
Jump to navigation Jump to search
No edit summary
No edit summary
(One intermediate revision by the same user not shown)
Line 17: Line 17:


The '''Tektronix 1A2''' is a two-channel plug-in amplifier for [[500-series scopes]].
The '''Tektronix 1A2''' is a two-channel plug-in amplifier for [[500-series scopes]].
It provides a −3 dB point of 50 MHz in a [[544]], [[546]], [[547]], or [[556]], and 50 mV/div sensitivity.
It provides a −3 dB point of 50 MHz in a [[544]], [[546]], [[547]], or [[556]], and 50 mV/div sensitivity.  
It was designed by [[Larry Biggs]].


The Type 1A2 was [[introduced in 1964]] together with Types [[1A1]], [[543|543B]], [[545|545B]], [[544]], [[546]], and [[547]].
The Type 1A2 was [[introduced in 1964]] together with Types [[1A1]], [[543|543B]], [[545|545B]], [[544]], [[546]], and [[547]].
Line 32: Line 33:
1A1 and 1A2 share some mechanical design, but the circuits have few details in common.
1A1 and 1A2 share some mechanical design, but the circuits have few details in common.


The 1A2 uses a [[7586]] [[nuvistor]] at the front end as a cathode follower.
Below serial number 11000, the 1A2 uses a [[7586]] [[nuvistor]] at the front end as a cathode follower.
Then one input of an NPN differential amplifier is driven to produce a differential current-mode signal at the collectors.
Above serial number 11100, the front-end uses a FET for this function.
After the front-end buffer, one input of an NPN differential amplifier is driven to produce a differential current-mode signal at the collectors.


Silicon diodes form an analog multiplexer that switches between the two inputs.
Silicon diodes form an analog multiplexer that switches between the two inputs.

Revision as of 19:00, 31 January 2021

Template:Plugin Sidebar 2

The Tektronix 1A2 is a two-channel plug-in amplifier for 500-series scopes. It provides a −3 dB point of 50 MHz in a 544, 546, 547, or 556, and 50 mV/div sensitivity. It was designed by Larry Biggs.

The Type 1A2 was introduced in 1964 together with Types 1A1, 543B, 545B, 544, 546, and 547. It was designed to replace the venerable Type CA, while the 1A1 delivered ten times the sensitivity at a higher price and is able to lock channel 1 to Type 547's timebase A and channel 2 to timebase B. On the other hand, Type 1A2 can select which channel provides triggering when the mainframe is set to Plug-In mode, for scopes having this feature (544, 546, 547, 549, 556, late 555).

The 1A2 remained available until the 500-series scope line was discontinued.

Key Specifications

  • please add

Internals

1A1 and 1A2 share some mechanical design, but the circuits have few details in common.

Below serial number 11000, the 1A2 uses a 7586 nuvistor at the front end as a cathode follower. Above serial number 11100, the front-end uses a FET for this function. After the front-end buffer, one input of an NPN differential amplifier is driven to produce a differential current-mode signal at the collectors.

Silicon diodes form an analog multiplexer that switches between the two inputs. A cross-coupled pair of PNP transistors forms a multivibrator that generates the voltages that control the diodes that select the input channel.

Pictures