Operating Information Section; And Specifications; Introduction; Electrical - Tektronix 221 Instruction Manual

OPERATING INFORMATION
INTR O D U C TIO N
The 221 Oscilloscope is a single-channel, five megahertz
portable instrument using all solid state and integrated
circuit components (except the crt). The instrument is
mechanically constructed to withstand the shock, vibration,
and other extremes associated w ith portability.
The dc to five megahertz vertical system provides verti­
cal deflection factors from five m illivolts to 100 volts/
division at the tip of the integral high-impedance probe.
The trigger circuit provides stable triggering over the fu ll
range of vertical frequency response.
The horizontal deflection system provides calibrated
sweep rates from 200 milliseconds to one microsecond/
division. A sweep variable decreases calibrated sweep rates
by about 2.5:1, resulting in a minimum uncalibrated sweep
rate of about 0.5 second/division. A calibrated X10 sweep
magnifier increases the sweep to at least 0.1 microsecond/
division. In addition, horizontal amplifier operation pro­
vides a horizontal deflection factor o f one volt/division for
X-Y operation. The cathode-ray tube has a six by ten
division graticule (each division
0.2 inch).
The 221 is operated either from ac line voltage or from
internal rechargeable batteries. The internal batteries are
recharged from the ac power line by the integral battery
charger (with the instrument on or o ff).
This instrument w ill meet the follow ing electrical char­
acteristics after complete instrument calibration. These
characteristics apply over an ambient temperature range of
—15°C to +55°C (+5°F to +131°F) when battery operated,
or 0°C to +40°C (+32°F to +104°F) when the instrument is
connected to ac line voltage. Warmup tim e for given
accuracies is five minutes.

ELECTRICAL

The 221 oscilloscope w ill meet the following electrical
specifications after calibration. The check portion of the
calibration procedure provides a convenient method of
checking instrument performance w ithout making internal
checks or adjustments.
REV. B, FEB. 1976

AND SPECIFICATIONS

equals approximately
The following electrical characteristics apply over an
ambient temperature range of —15°C to +55°C (+5°F to
+131°F) battery operation, or 0°C to +40°C (32°F to
+104°F) for line voltage operation.

Vertical Deflection System

Calibrated Range: five m illivolts to 100 volts/division in
14 steps.
Accuracy: w ithin 3% w ith VAR VO LTS/D IV in CAL
detent position.
Uncalibrated VAR VO LTS/DIV range: Continuously
variable, 3:1 minimum.
Bandwidth (with six division reference): to at least
five megahertz (—3 dB point), with V A R IA B LE VOLTS/
DIV in CAL position.
Step Response: 70 nanoseconds or less.
Aberrations: +5%, — 5%, 5% peak to peak total.
Input Resistance: 1 megohm.
Input Capacitance: Approximately 29 picofarads.
Maximum Safe Input Voltage: 600 volts (dc + peak ac),
600 volts peak-to-peak ac.

Triggering

Trigger Sensitivity:
INT: 0.5 divisions from two hertz to one megahertz,
increasing to 1 division at five megahertz.
EXT: 0.5 volt from dc to one megahertz; increasing
to 1 volt at 5 megahertz.
AUTO PRESET: Triggered at preset level on positive
slope of waveform.
Display Jitter: 20 nanoseconds or less.
EXT TRIGGER:
Input Resistance: Approximately one megohm.
Input Capacitance: Approximately 30 picofarads.
Maximum Usable Input Voltage: Three volts (dc +
peak ac), six volts peak-to-peak ac (five megahertz of less).
Section 1—221 Service
1-1