The specifications I found for the 2N2207 were Vceo = 50 volts and
Vcbo = 70 volts. When the blanking signal is applied to the emitter
and the base driven by a relatively low impedance -0.6 volts, the Vcbo
is a better match.
But even a Vcbo of 70 volts is not much greater than the -68 volts
marked on the schematic. Maybe Tektronix graded them for a higher
minimum breakdown voltage.
On Tue, 09 Oct 2012 21:31:25 -0000, "Albert" <aodiversen@...>
wrote:
No, for 151-063 (= 2N2207) Vceo = 70 V, but even then ...
Albert
Hi David,
you say "operating close to its breakdown voltage", then you are joking.
V_ceo is 50 volts and in the schematics, the difference between E and C
is over 67 volts !!
They are working "beyond the cliff" !
Herbert
David Hess