On Sun, Feb 2, 2025 at 12:35 AM, Mike M wrote:
So even though the 2SC3357 has a higher fT than the 2SC5551, it did not oscillate.
Thank you sharing your experiences, mike.
That fits to my observations, that a transistor with a higher fT is not automatically more prone to oscillation than a transistor with lower fT.? But they are able to oscillate at higher frequencies. Modern high fT RF-transistors of newer silicon-processes have normally lower junction capacitances, e.g. a lower feedback capacitance and a lower collector capacitance. These capacitors are components of a feedback network that forms,? together with external parasitic reactances, an oscillating device. The BFU590 in my experience ist not particularly critical in terms of parasitic oscillation.
?
regards
Fred
