Z-Axis Amplifier - Tektronix 2215 Instruction Manual

The nonlinear current is connected to the em itters o f
the differential am plifier composed o f Q811 and Q812.
The emitters o f the tw o a m plifier transistors are held at a
constant voltage by the action o f Q813. A U T O IN T E N ­
S ITY control R807 is connected to the base o f Q811 via
R 811. It controls the p o rtio n o f the boost current th a t goes
to the summing junction o f U835B. Boost current is pro­
portional to the true beam current required at the faceplate
o f the crt.
The c rt trio d e compensation c irc u it is an inverting
operational am plifier
composed o f U835B, R834, R835, C834, and CR834.
O utp ut voltage o f the c irc u it changes in response to the
in pu t current in a manner th a t complements the nonlinear
trio de characteristics o f the crt. This o u tp u t voltage is
applied both to the Intens Level signal line and to the
Z-Axis A m p lifie r via the A and B Z-A xis Logic Switching
circuits. The Intens Level signal is also applied to the Focus
c irc u it (Diagram 9) fo r use in focus tracking o f the intensity
level changes.
The intensity o f the display is allowed to reduce to zero
through the action o f CR809, VR809, and R809. W ith o u t
this circuit, the A u to Intensity c irc u it w ould not allow the
intensity to go to zero when the A U TO
con tro l is set to m inim um intensity.

Z-Axis Amplifier

The Z-Axis A m p lifie r controls the c rt intensity level
via several input-signal sources. The effect o f these input
3-22
w ith nonlinear feedback. It
IN T E N S IT Y
is