PTO222

Material/Aufbau/Pol.: Germanium Legierung PNP;
Form/Case/Outline: TO-5;
Daten/electr.data: I F: __ mA; U F: __ V; U S: __ V; Isp: __ µA; ß (beta): __; N: __ mW; Imax(Ic): __ mA; Umax(Ucb): -__ V; Umax (Uce): -__ V; f g (FT): __ MHz; tmax j: __ °C.
(no data available yet) - manufactured by Mistral (I)

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Judging from the information available up to date (January 2024) in RMorg, the PTOxxx types were used to stabilize the base to base voltage difference of Germanium transistors in push-pull audio output amplifiers, thus ensuring stable quiescent DC- current.

Other approaches to achieve this goal include (i) connecting the bases by a simple resistor (sometimes in combination with an NTC - resistor), through which a constant DC - current is passed, or (ii) using a low - voltage ZENER diode like ZG1 and adjusting the voltage drop (~ 0,7 V) by a resistive divider to suit the desired base to base voltage difference.