190: Difference between revisions

190 (view source)

890 bytes added , 5 July 2014

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 often undesirable.  Having a constant-amplitude source simplifies the measurement.
+The oscillation frequency of the 190B is controlled
+by a rotary variable capacitor.
+The variable capacitor rotates together with a drum
+that serves as the frequency readout dial.
+The drum is made of cream colored plastic
+and has a diameter of 5" (12.5cm) and a height of 4" (10cm).
+The frequency knob on the front panel of the 190B
+turns a rubber wheel which, by friction, turns the drum.
+The relatively large diameter of the drum provides for
+precise frequency control,
+long effective length of the readout dial, and
+ensures that the friction coupling between the frequency knob and the drum
+provides sufficient torque to turn the drum and rotary capacitor without any slippage.
 * [http://bama.edebris.com/download/tek/190/190.djvu Tektronix 190 Manual (DjVu)]
 * [http://w140.com/tek_190ab.pdf Tektronix 190 Manual (PDF)]
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 <gallery>
 File:Tek 190b front.jpg|190B
+File:Tek 190b left1.jpg|190B
+File:Tek 190b right2.jpg|190B
+File:Tek_190b_right1.jpg|190B
+File:Tek 190b left2.jpg|190B
+File:Tek 190b drum control wheel.jpg|Rubber wheel rotating frequency drum in 190B
 Image:Tek 190b attenuator.jpg|190B attenuator
 Image:Tek 190b attenuator_entire.jpg|190B attenuator
 Image:Tek 190b attenuator connector.jpg|190B attenuator connector
 </gallery>