At Mod Wiggler I've found some hints and a circuit for transistor matching. I've built that circuit on stripboard and now can start with the transistor matching: The TTSH design uses various pairs of 2N3904 and 2N3906 transistors. These pairs should each have a very similar base-emitter voltage (within 2 mV difference).

Transistor Matching Circuit Board20150307_002845_4778c
Transistor Matching Circuit Board
Transistors 2N3904 and 2N3906 ready to be tested.
Transistor Matching Circuit Board

Transistor Matching Circuit Board, wiring side20150307_003223_4780cr
Transistor Matching Circuit Board, wiring side
Transistor Matching Circuit Board, wiring side

And here we go for the matching. Measuring transistor after transistor:

Measuring Base-Emitter Voltage of a Transistor20150307_175234_4782
Measuring Base-Emitter Voltage of a Transistor
Measuring Base-Emitter Voltage of a Transistor

All 2N3904 NPN transistors are pretty equal, with a base-emitter voltage of 615mV to 617mV. The 2N3906 PNP transistors spread a little more, from 603mV to 609mV, but many with 606mV or 607mV.


Built with Pelican · © 2022 Campacasa