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The Tektronix 112 is a DC-coupled differential amplifier [[introduced in | [[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 | 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 | |||
The | 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. | ||
a | The amplifier's schematic and response are identical to that of a [[512|Tek 512]]. | ||
The | 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)] | ||
==See Also== | |||
* [[121]] | |||
==Photos== | |||
<gallery> | <gallery> | ||
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]] |