The Model 538 is a compact, highly reliable, universal purpose oscilloscope which employs compact 75mm round screen cathode-ray tube, solid-state electronics, and unique light weight metallic alloy housing The vertical system provides a sensitivity of 1 0 mV/div or over and a frequency bandwidth of DC~ 1.5 MHz. It has a direct CRT input terminal. The time axis circuit provides sweep frequencies of 10 Hz ~ 100 kHz sweep and synchronizing with INT M - ” only. When this circuit is switched over to the external sweep mode, it provides a deflection sensitivity of 250 mV/d or over and a frequency band of DC ~ 500 kHz. The external signal is applicable through a front panel terminal. This mode can be employed for X - Y operation of the oscilloscope, providing a high operation flexibility. Since solid-state, electronics is employed throughout the circuits, the oscilloscope can start operating only in less than 20 seconds after its power is turned on. Since heat-generating components and hence the instrument wattage are minimized, the drift is very small and an improved operation reliability is__attained.