The HP 54713A plug-in is a 500-MHz high-impedance amplifier plug-in designed to accommodate high-impedance resistive divider probes. It allows users to connect to or probe circuits that cannot drive 50-ohm loads or the low resistance of resistive divider probes (500 or 1000 ohms). The input to the HP 54713A is 1 megohm shunted by 7 pF. The 500-MHz bandwidth is adequate for many applications and allows various types of signal conditioning such as ac or dc coupling, switchable 50-ohm termination, and low-pass and high-pass filtering for removing noise when needed. Also, the 500-MHz bandwidth is only one fourth of the sample rate of 2 GHz, which helps limit aliasing for real-time measurements. The HP 54713A uses the same high-impedance attenuator/amplifier as the HP 54500 Series of benchtop oscilloscopes. This is a thick-film hybrid circuit containing a mechanical attenuator and a bipolar IC housed in a custom shield. The use of this integrated attenuator/preamplifier allows the HP 54713A to provide a general-purpose oscilloscope front end at a reasonable price per channel.