112: Difference between revisions

From TekWiki
Jump to navigation Jump to search
No edit summary
No edit summary
(24 intermediate revisions by 2 users not shown)
Line 1: Line 1:
The Tektronix 112 is a DC-coupled differential amplifier [[introduced in 1955]].   
[[File:Tek 112 front.jpg|thumb|200px |right]]
The '''Tektronix 112''' is a DC-coupled differential amplifier [[introduced in 1949]].   
The voltage gain can be set from 0.5 to 5000 V/V.   
The voltage gain can be set from 0.5 to 5000 V/V.   
The frequency response is DC to 2MHz when the gain is set
The frequency response is DC to 2 MHz when the gain is set below 166, and DC to 1 MHz for gain settings greater than that.  
below 166, and DC to 1MHz for gain settings greater than that.
The 121 is intended for use with the
[[511]], [[512]], [[514]], and [[524]] oscilloscopes.
The input impedance is 1 megohm in parallel with 47 pF.
The output impedance is 8000 ohms.  The amplifier's
response is identical to that of a Tek 512.


The 112 is intended for use with the [[511]], [[512]], [[514]], and [[524]] oscilloscopes.
The input impedance is 1 MΩ in parallel with 47 pF. The output impedance is 8000 Ω. 
The amplifier's schematic and response are identical to that of a [[512|Tek 512]].
The first stage is a differential amplifier using a pair of [[5879]] pentodes. 
Next is a differential amplifier using a pair of [[12AU6]] pentodes. 
The 112 has a differential output intended for directly driving the vertical deflection plates of a CRT.
The output terminals of the 112 are on the right side in the rear, so the 112 can sit to the left of an oscilloscope
and short wires can connect the 112 to the oscilloscope's CRT.
A two-position switch on the rear panel of the Type 112 controls the common-mode output voltage.
In one position, the common-mode output voltage is +150 V,
which is the plate voltage of the [[6AG7]] tubes of the output amplifier.
In the other position, the common-mode output voltage is 0 V.
The shifting of the common-mode output voltage 150 V downward is accomplished
by enabling a pair of 680 μA DC current sinks that cause a voltage drop on 220 kΩ series output resistors.
[[6CB6]] pentodes form the current sinks, with their cathodes tied to -150 V.
The 220 kΩ output resistors also provide short circuit protection.
The Type 112 manual recommends 0 V for driving the CRT of the [[511]],
and +150 V for driving the CRT of the [[512]], [[513]], or [[514]].
==Manuals==
* [http://w140.com/tek_112.pdf Tektronix 112 Manual (PDF)]
* [http://w140.com/tek_112.pdf Tektronix 112 Manual (PDF)]


Photos needed.
==See Also==
* [[121]]


==Photos==
<gallery>
<gallery>
Image:Tek 112.jpg|1955 Catalog photo
tek_112_18.jpg
Tek 112.jpg|1955 Catalog photo
Tek 112 front.jpg|Manual photo
Tek 112 main schematic.png|Main schematic
Tek_112.power_supply.png|Power Supply Schematic
Tek 112 calibrator schematic.png|Calibrator Schematic
tek_112_10.jpg|Bottom deck. Fan is missing; fan yoke still present.
tek_112_11.jpg
tek_112_13.jpg|Underside of bottom deck, front.
tek_112_14.jpg|Underside of bottom deck, rear.
tek_112_15.jpg|Underside of top deck.
tek_112_16.jpg|Vibration-isolated front-end amplifier
tek_112_20.jpg|Deflection sensitivity switch.
tek_112_3.jpg|Top internal
tek_112_4.jpg|Top front internal
tek_112_5.jpg|Top rear internal
tek_112_6.jpg
tek_112_7.jpg
tek_112_8.jpg|Left rear. Power supply tubes on the left: three [[5V4G]] rectifiers (one missing) and one [[6AS7]] triode series pass tube.
tek_112_9.jpg|Rear of front panel has sockets for holding spare tubes.
tek_112_2.jpg
tek_112_1.jpg
</gallery>
</gallery>
[[Category:Differential amplifiers]]
[[Category:Introduced in 1949]]

Revision as of 08:14, 8 August 2020

The Tektronix 112 is a DC-coupled differential amplifier introduced in 1949. The voltage gain can be set from 0.5 to 5000 V/V. The frequency response is DC to 2 MHz when the gain is set below 166, and DC to 1 MHz for gain settings greater than that.

The 112 is intended for use with the 511, 512, 514, and 524 oscilloscopes. The input impedance is 1 MΩ in parallel with 47 pF. The output impedance is 8000 Ω. The amplifier's schematic and response are identical to that of a Tek 512.

The first stage is a differential amplifier using a pair of 5879 pentodes. Next is a differential amplifier using a pair of 12AU6 pentodes.

The 112 has a differential output intended for directly driving the vertical deflection plates of a CRT. The output terminals of the 112 are on the right side in the rear, so the 112 can sit to the left of an oscilloscope and short wires can connect the 112 to the oscilloscope's CRT. A two-position switch on the rear panel of the Type 112 controls the common-mode output voltage. In one position, the common-mode output voltage is +150 V, which is the plate voltage of the 6AG7 tubes of the output amplifier. In the other position, the common-mode output voltage is 0 V. The shifting of the common-mode output voltage 150 V downward is accomplished by enabling a pair of 680 μA DC current sinks that cause a voltage drop on 220 kΩ series output resistors. 6CB6 pentodes form the current sinks, with their cathodes tied to -150 V. The 220 kΩ output resistors also provide short circuit protection. The Type 112 manual recommends 0 V for driving the CRT of the 511, and +150 V for driving the CRT of the 512, 513, or 514.

Manuals

See Also

Photos