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The Tektronix Type L is plug-in for [[500-series scopes]].
{{Plugin Sidebar
|manufacturer=Tektronix
|series=500-series scopes
|type=Type L
|summary=High sensitivity amplifier plugin
|image=Tek type l front.jpg
|caption=Tektronix Type L
|introduced=1957
|discontinued=1973
|designers=Ron Olson
|manuals=
* [[Media:070-336.pdf|Tektronix Type L Manual]] (PDF, OCR)
* [[Media:tek_type_l_fcp.pdf|Tektronix Type L Factory Calibration Procedure (PDF, OCR, bad-OCR)]]
* [[Media:Tek type l cal outline.pdf|Tektronix Type L Calibration Outline (PDF, OCR)]]
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* [https://w140.com/mmm/tek-l.pdf Tektronix Type L Manual (PDF)]
* [https://w140.com/tek_fcp/tek_type_l_factory_cal_proc.pdf Tektronix Type L Factory Calibration Procedure (PDF)]
-->
}}
The '''Tektronix Type L''' is an amplifier plug-in for [[500-series scopes]].


* http://bama.edebris.com/manuals/tek/l/
The Type L is a [[K|Type K]] plus a 10x-gain AC-coupled preamp
* http://w140.com/tek_fcp/tek_type_l_factory_cal_proc.pdf
that extends the maximum sensitivity to 5 mV/div.
Bandwidth in a [[545]] is 30 MHz at 50 mV/div and above, 3 Hz-24 MHz at 20 mV/div and below.
 
Type 53/54L was [[introduced in 1957]] along with the [[536]] and its companion
[[T|53/54T]] sweep plug-in.  It was renamed the Type L in 1959.
It was the fastest 5 mV plug-in until the [[1A1]] in 1964.
It was dropped after 1972.
 
[[K]], L, and [[T]] are tied for longest production life, at 16 years.
[[B]], [[D]], and [[G]] are next at 15 years.
 
Late versions have a [[BNC connector]] instead of a [[UHF connector]].
 
[[Lavoie Laboratories]] produced an unauthorized clone, the [[Lavoie LA-265-L|LA-265-L]].
 
{{MissingSpecs}}
 
==Internals==
 
The input signal traverses a frequency-compensated attenuator network controlled by the Volts/cm switch,
and is then coupled to the first cathode follower tube (V5832), a [[5654]]/[[6AK5W]] RF pentode.
The screen supply of this cathode follower is switched from +100 V to a decoupling
network fed from the +225 V rail when the ×10 Mode is selected.
 
The output of input amplifier is then switched via a 10× amplifier (if ×10 mode is selected) or
directly to the paraphase or phase inverter made up of two [[12AU6]] tubes. This stage converts
the input signal to a differential push-pull output. This output is passed to the final output drivers,
which are two cathode follower sections with a pair of [[12AT7]] tubes. The differential output is then
passed to pin 1 and 3 of the connector to drive the vertical amplifier inside the chassis.
 
The ×10 amplifier stage is built with three 5654/6AK5W tubes, the first two of which are configured as
amplifiers, and the last one as an output cathode follower.
The diode D5972 on the first 5654/6AK5W amplifier tube's cathode (V5942) is used to protect the cathode bypass capacitor C5972, a 500 μF/6 V electrolytic, in case someone would pull out V5942 with power applied,
in which case the cathode bias of −150 V would come across C5972 and destroy it.
 
Heater supplies for the tubes are derived from the +75 V<sub>DC</sub> supply available at pin 15 of
the mainframe interface, to avoid any mains interference/hum from the regular AC heater supply.
 
==Pictures==


<gallery>
<gallery>
Image:Tek type l.jpg
type L front.jpg
Tek type l.jpg
Tek type l top.jpg
Tek type l left.jpg
Tek type l bottom.jpg
Tek type l in 541a.jpg|Type L in [[541|541A]]
Tek type l perf.png | Performance in Different Scopes
Tek type l schem.png | Schematic
</gallery>
</gallery>
[[Category:500 series plugins]]

Revision as of 03:43, 17 August 2021

Tektronix Type L
High sensitivity amplifier plugin
Tektronix Type L

Compatible with 500-series scopes

Produced from 1957 to 1973

Manuals
Manuals – Specifications – Links – Pictures

The Tektronix Type L is an amplifier plug-in for 500-series scopes.

The Type L is a Type K plus a 10x-gain AC-coupled preamp that extends the maximum sensitivity to 5 mV/div. Bandwidth in a 545 is 30 MHz at 50 mV/div and above, 3 Hz-24 MHz at 20 mV/div and below.

Type 53/54L was introduced in 1957 along with the 536 and its companion 53/54T sweep plug-in. It was renamed the Type L in 1959. It was the fastest 5 mV plug-in until the 1A1 in 1964. It was dropped after 1972.

K, L, and T are tied for longest production life, at 16 years. B, D, and G are next at 15 years.

Late versions have a BNC connector instead of a UHF connector.

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

Key Specifications

  • please add

Internals

The input signal traverses a frequency-compensated attenuator network controlled by the Volts/cm switch, and is then coupled to the first cathode follower tube (V5832), a 5654/6AK5W RF pentode. The screen supply of this cathode follower is switched from +100 V to a decoupling network fed from the +225 V rail when the ×10 Mode is selected.

The output of input amplifier is then switched via a 10× amplifier (if ×10 mode is selected) or directly to the paraphase or phase inverter made up of two 12AU6 tubes. This stage converts the input signal to a differential push-pull output. This output is passed to the final output drivers, which are two cathode follower sections with a pair of 12AT7 tubes. The differential output is then passed to pin 1 and 3 of the connector to drive the vertical amplifier inside the chassis.

The ×10 amplifier stage is built with three 5654/6AK5W tubes, the first two of which are configured as amplifiers, and the last one as an output cathode follower.

The diode D5972 on the first 5654/6AK5W amplifier tube's cathode (V5942) is used to protect the cathode bypass capacitor C5972, a 500 μF/6 V electrolytic, in case someone would pull out V5942 with power applied, in which case the cathode bias of −150 V would come across C5972 and destroy it.

Heater supplies for the tubes are derived from the +75 VDC supply available at pin 15 of the mainframe interface, to avoid any mains interference/hum from the regular AC heater supply.

Pictures