The 211 Oscilloscope is a single-channel, 500 kilohertz portable instrument using all solid state and integrated circuit components (except CRT). The small size of the 211 makes it an extremely portable oscilloscope for on-location maintenance in many fields of application. The instrument is mechanically constructed to withstand the shock, vibration, and other extremes associated with portability. The DC to 500 kilohertz vertical system provides vertical deflection factors from one millivolt (at reduced bandwidth) to 50 volts/division at the tip of the high-impedance probe. The trigger circuits provide stable triggering from about seven hertz to 500 kilohertz from either an internal or external source. The horizontal deflection system provides calibrated sweep rates from 200 milliseconds to five microseconds/ division. A continuously variable sweep magnifier provides uncalibrated sweep rates to at least five times the indicated sweep rate, for a maximum sweep rate of at least one microsecond/division. In addition, horizontal amplifier operation provides horizontal deflection factors of one and 10 volts/division. The resultant CRT display produced by the vertical and horizontal deflection systems is presented on a 6 X 10 division graticule (each division equals 0.203 inch). The 211 can be operated either from AC line voltage or from internal rechargeable batteries. Maximum total power consumption is two watts. The internal batteries can be recharged from the AC power line by the integral battery charger (instrument off). This instrument will meet the following electrical characteristics after complete instrument calibration as given in Section 4. Section 4 also provides a convenient method of checking instrument performance without making internal checks or adjustments. The following electrical characteristics apply over an ambient temperature range of —15°C to +55°C, except as otherwise indicated. Warmup time for given accuracy is five minutes.