Tektronix 5T1A Instrument Reference Book page 12

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SERIAL
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The Type 290 does not use speedup capacitors or catch-
ing diodes. Use of these capacitors and diodes tends to
test a circuit rather than a transistor. The common emitter,
base-driven circuit of the Type 290 introduces into the base
of the test transistor a non-overshooting step of current
equal to 1 ma/volt of input pulse in excess of Vibe.
The collector circuit provides a resistive load of 200
ohms monitored by an internal dc-coupled passive probe,
for measurement of collector-to-emitter saturation potentials
and collector swings under saturated or linear conditions.
Transistor input and output are presented in correct time
relationship either simultaneously for dual-trace systems or,
at the turn of a switch, for single-trace systems. The input
monitor and output of the Type 290 Transistor Switching-
Time Tester is at a 50-ohm impedance level, allowing remote
location of the tester from the sampling system.
TWO TRANSISTOR TEST SOCKETS are mounted on the
Type 290. The sockets provide for easy insertion of the tran-
sistor into the grounded-emitter test circuit. One socket
connects to the HIGH collector voltage supply and the other
connects to the LOW collector voltage supply. A transistor
under test in the HIGH socket has a passive probe output
attenuation of 250-to-1 into the 50-ohm output. A transistor
under test in the LOW socket has an attenuation of 50-to-]
from the collector to the 50-ohm output. Lead length of the
transistor tested, up to approximately 2 inches, is unim-
portant at speeds slower than 2 nsec, due to the choice of
collector load resistance.
THREE 50-OHM CONNECTORS for input, output, and
input monitor are conveniently mounted at the side of the
instrument.
INPUT from external pulse generator determines base
current of transistor under test. For each volt of input pulse
above Vp. there is approximately 1 ma of base current.
OUTPUT signal is taken from the collector of the transistor
under test. The input signal can be switched to the output
for observation with a single trace system.
INPUT MONITOR permits simultaneous viewing of the
input and output of the transistor under test when used with
TYPE 290 TRANSISTOR
SWITCHING-TIME TESTER
The Tektronix Type 290 Transistor Switching-Time Tester
permits dc-coupled pulse-response characteristics of fast-
switching transistors to be observed and measured on Tek-
tronix oscilloscopes. Driven by a Tektronix fast-rise pulse
generator and combined with a Tektronix fast-rise sample
oscilloscope, the Type 290 becomes an integral part of a
transistor testing system with an overall transient response
of less than 1 nanosecond. (When a non-sampling oscillo-
scope is used with plug-in units such as the Type 82, or
L, transient response is limited by the risetime of the unit).
This system can test fast NPN or PNP transistors on a short
duty-cycle basis for delay, rise, storage, and fall times —
with variable collector voltage and base drive conditions.
Since these characteristics vary considerably with operating
conditions, the Type 290 supplies a wide range of operat-
ing voltages.
a dual-trace unit such as the Type 4S1, 482, or Type 3S76.
The input monitor has a 50-to-1 attenuation ratio.
REGULATED SUPPLIES (with Zener diodes) are provided
for the collector and base supply sources. Collector Voltage
is continuously variable from zero to 30 volts in the LOW
position and from zero to 100 volts in the HIGH position.
Base Supply Voltage is continuously variable from zero
to £10 volts (through 10k).
POWER REQUIREMENT is 105v to 125v or 210v to
250 v, 50 to 1200 cps, 15 watts.
MECHANICAL FEATURES include aluminum-alloy chassis,
die-cast aluminum top and bottom covers (with steel, wrap-
around housing), and etched circuit-board chassis. Overall
dimensions are 73/," high by 75/3" wide by 5" deep. Net
weight is 5 pounds. Shipping weight 9 pounds, approx.
TYPE 290 TRANSISTOR SWITCHING-TIME TESTER .... $290
Includes: 2 — instruction manuals, 1 — 10-nsec cable, 1 —
3-conductor power cord.
10 nsec/cm
Fast Switching Transistor
Equivalent to Ip, (turn-on) = 12 ma (approx)
IB, (turn-off) — 0.1 ma (approx)