GENERAL. Although deceptively simple in appearance and operation the bwd 504 is a calibrated oscilloscope with a wide measurement capability in Voltage, Time, Frequency, Phase & Current. When required the input terminals can be isolated from the power line ground by removal of a ground link. This enables measurements to be made between voltages not at ground potential up to a limit of±400V DC. It may also be used to eliminate ground loops from low level signals. Additionally it prevents accidental connection of a lead from the ground terminal to a live voltage from shorting out equipment - a particularly useful feature in educational areas. As both vertical and horizontal amplifiers are DC coupled the bwd 504 will measure both DC and AC voltages from the mi11ivolt range to over 400V. If a 1 Ω resistor is placed across the input terminals the current flowing through it when connected into a circuit is displayed on the CRT directly in milliamps or amps. Time periods from less than 0.5|j Sec to 1 Sec are readily measured or degrees of phase shift over the range DC to 50kHz. Frequency comparison by lissajous figures can extend from zero frequency to beyond 1MHz. Although the specified bandwidths of the bwd 504 is 6MHz at - 3db its amplifier response does in fact extend to well over 25MHz. A chart in the operation section shows how to make measurements over this extended frequency range, together with charts for rise time and phase measurements. A range of high impedance and demodulator probes are available to further extend the measurement ability of your bwd 504. Check the bwd accessory list.