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Argus25 · 17th Apr 2019, 1:11 am

Pondering this some more. Somebody decided the OC35 would work . I don't know the max voltage the transistor is exposed to in your circuit.

A lower voltage rated (than the 2N2147) but with a good minimum hfe of 50 is the vintage (and classic) NKT404, by Newmarket. These were one of the most widely used TO-3 germanium power transistors in the UK in the 1960's and used for many amateur radio analog psu projects and even switching supplies such as Royer DC converters. These may be an option if the voltage ratings are not exceeded by your circuit.

17th Apr 2019, 1:11 am	#17
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: Replacement power transistors hfe. Pondering this some more. Somebody decided the OC35 would work . I don't know the max voltage the transistor is exposed to in your circuit. A lower voltage rated (than the 2N2147) but with a good minimum hfe of 50 is the vintage (and classic) NKT404, by Newmarket. These were one of the most widely used TO-3 germanium power transistors in the UK in the 1960's and used for many amateur radio analog psu projects and even switching supplies such as Royer DC converters. These may be an option if the voltage ratings are not exceeded by your circuit.