The 1N3129  (P/N 152-0043-00) is a 20 mA Germanium tunnel diode in a DO-25var package.

1N3129 on quarter dollar

Some instruments using part 1N3129

Instrument Manufacturer Class Model Description Introduced
3T77 Tektronix Plug-in 3T77 Sampling sweep plug-in 1962
5T1 Tektronix Plug-in 5T1 Sampling sweep unit 1961

Key Specifications

Peak current 20 ± 1 mA
Capacitance 20 pF
Peak to valley current ratio min. 8.0
Peak voltage 100 mV
Valley voltage 300 mV
Forward voltage at peak current 575 mV
Series inductance 0.6 nH
Series resistance 2.5 Ω
Temperature max. 100 °C