The 7A12 vertical amplifier plug-in is designed for use with Tektronix 7000-Series Oscilloscopes. The 7A12 is a dual-channel, wide band amplifier with the upper frequency limit mainly determined by the oscilloscope mainframe in which it is used. For example, the 7A12 used with the 7504 oscilloscope will have an upper bandwidth limit of about 75 MHz. When used with a 7704 oscilloscope, the upper bandwidth limit is about 105 MHz. Internal gain and compensation circuits are automatically switched to correspond to the setting of the VOLTS/DIV switch. A +UP/INV switch for each channel allows either channel to be inverted for differential measurements. The 7A12 features a DC offset circuit with a DC offset of at least ±500 divisions for viewing low level AC signals in the presence of a high level DC component.