Hello community,
Today I was testing some 2N3904 NPN bipolar junction transistors, which according to the datasheet, is capable of switching up to 300 MHZ. I do not expect a very accurate response at high frequencies, however, I tested a 5 vold DC square wave with a 50% duty cycle generated by a 555 timer, and the transistor was only getting up to 1.5 VDC with a 30 KHZ square wave. I thought that was strange, and perhaps I had bad transistors, so I went to a local shop and bought some 2N3904 and 2N3906. I got the same results. At 3 KHZ, the transistor gets up to about 3.5 VDC, it only reaches 4.6 VDC at an astonishingly slow 800 HZ!
Does anyone have any suggestions for a better alternative NPN and PNP transistor for switching?
Today I was testing some 2N3904 NPN bipolar junction transistors, which according to the datasheet, is capable of switching up to 300 MHZ. I do not expect a very accurate response at high frequencies, however, I tested a 5 vold DC square wave with a 50% duty cycle generated by a 555 timer, and the transistor was only getting up to 1.5 VDC with a 30 KHZ square wave. I thought that was strange, and perhaps I had bad transistors, so I went to a local shop and bought some 2N3904 and 2N3906. I got the same results. At 3 KHZ, the transistor gets up to about 3.5 VDC, it only reaches 4.6 VDC at an astonishingly slow 800 HZ!
Does anyone have any suggestions for a better alternative NPN and PNP transistor for switching?