The Model 150A dc to 10 mc oscilloscope is a general purpose oscilloscope employing a 5 AMP- monoaccelerator type cathode ray tube with unitized, plugin construction for maximum accessibility and flexibility. It can be used with either internal or external sweeps which can be either internally or externally synchronized. The horizontal amplifier incorporates magnification circuitry which is capable of expanding basic internal sweeps, up to 100 times. The internal sweep range extends from .02 µsec/cm to 15 sec/cm. The Model 150A uses a variety of vertical amplifier plug-in units to perform different functions. Since operation of the rack model is similar to that of the cabinet model, the operation of the instrument will be described without regard to style of mounting.