The Tektronix Type 290 Transistor Switching Time Tester is a test fixture introduced in 1962 with built-in power supplies for the collector current and the base bias. It handles NPN and PNP transistors. It has two modes: low-voltage and high-voltage. In the low-voltage mode, Vcc can be adjusted from 0V to 30V. In the high-voltage mode, Vcc goes from 0V to 100V. The fixture provides a 50-ohm input and a 50-ohm output with GR-874 connectors, so it can be used with standard cables and test instruments while maintaining good signal integrity. The instrument itself is rated to have a risetime of under 1 nanosecond.