221

From TekWiki
Jump to navigation Jump to search
Tektronix 221
5 MHz miniature analog scope
Tektronix 221

Produced from 1975 to 1991

Manuals
(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix Type 221 is a miniature 5 MHz analog scope introduced in 1973.

Key Specifications

Bandwidth DC to 5 MHz
Input Impedance 1 MΩ // 29 pF
Input Voltage max. 600 V DC + Peak AC, or 600 Vp-p AC
Sweep Range 200 ms to 1 μs, 17 steps
CRT 154-0705-00, 6 Div (V) × 10 Div (H), 1 kV acceleration
Operating Time on Battery 2-3 hours
Internal Battery 10 rechargeable NiCd cells
Line Voltage 90-250 VAC @ 48−62 Hz, or 80-250 VDC
Power Consumption 5 W @ 250 V
Dimensions (H/W/D) 3" × 5.25" × 9" (7.6 cm × 13.2 cm × 22.8 cm)
Weight 3.5 lb (1.5 kg)

Links

Documents Referencing 221

Document Class Title Authors Year Links
60AX-4741.pdf Application Note Floating Oscilloscope Measurements ... And Operator Protection 1981

Prices

Year 1976 1977 1980 1982 1986
Catalog Price $825 $975 $1,325 $1,600 $2,260
In 2023 Dollars $4,500 $5,000 $4,900 $5,100 $6,300

Internals

The 221 has a switching power supply and built-in rechargeable batteries (which area maintenance issue). It has a transformer-coupled trigger circuit which would seem to preclude DC level-based triggering. The trigger circuit uses a 1N3713 1 mA tunnel diode. The vertical output amplifier that drives the CRT plates is two op-amps made from discrete transistors. One drives the top deflection plate, the other the bottom plate.

The power supply in the 221 uses three transformers – 120-0876-00 (T633) in the line inverter, 120-0877-00/120-0946-00 (T623) in the base drive for the line inverter and 120-0875-00 (T701) in HV inverter.

The 221 contains one integrated circuit, a 741 op-amp that creates a virtual ground, otherwise only discrete (including dual) transistors.

MOD 290A is a version of the 221 made for IBM which adds a Single Sweep function and a "Property of IBM" engraving.

Pictures

Internals

Components

Some Parts Used in the 221

Part Part Number(s) Class Description Used in
120-0876-00 120-0876-00 Discrete component pot core transformer 221
154-0705-00 154-0705-00 CRT CRT for miniature scopes 221
STD933 152-0181-00 Discrete component 1 mA, 5 pF germanium tunnel diode 1S2 221 422