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10 Threads found on bf199
If you use those AC transistors at stand of bf199, the oscillator may not oscillate.This is valid for Q2 too.( Amplification may be low or insufficient) Because RF transistors are quite different than AC Low Frequency transistors and the design has been done for these transistors mentioned, But it's worthy to try,they can also work .. For RF ci
Hi,I would like to find out the values of Cs,Cp,Ls and Rs of the crystal for creating oscillations of 28Mhz. my circuit is: this only forms my first stage and the bf199 is important as i need to go on to make a 2W 85Mhz transmitter. i have tried few values but the oscillations just won't start. any suggestions? plz help. Hi
Hi Mk16820, after a quick check with some datasheets, it seems 1) BF494 and bf199 are not drop-in (i.e. 100% compatible, at least in elec specs). Hfe and cut-off frequencies are different. The latter is bigger in bf199. These can be problematic in some RF application. 2) Similary 549 and 547 have also some differencies, like Vceo, Vcbo, NF etc.
is a 30W transmitter. Generator is based on transistor BC548. The device is also equipped with separators on BF245 and bf199, 1 grade ? also bf199, then 2N2219, KT907a and KT909G. The transmitter should have a low pass filter. The transmitter has a stereo encoder (with 50us pre-emph
i use bf199 & sft10.7 (ceramic filter) in my circuit & encounter this problem ; no pspice template .please help me its very necessary.
Hi, Yes, you can use bf199 instead of BF197 transistor. It will also amplify about the same around 100MHZ in that circuit your link shows because its unity gain transit frequency is around 400-500MHz.
.MODEL bf199 NPN ( + IS = 1e-14 + BF = 100 + BR = 1 + RB = 0 + RE = 0 + RC = 0 + CJS = 0 + CJE = 2e-12 + CJC = 2e-12 + VJE = 0.75 + VJC = 0.75 + TF = 2.6126e-10 + TR = 1e-08 + MJE = 0.33 + MJC = 0.33 + VA = 100 + ISE = 0 + IKF = 0.01 + NE = 1.5 + NF = 1 + NR = 1 +
use the model.
2N4401 = BC337a, BC637, BC639, 2N2221, 2N2222 MPSH34 = bf199, BF224, BF311, BF373, BF497 Ante :roll:
Give us schematics of amplifier. I think it's better to use BFR90 if you want to make widebandwidth amplifier. bf199 has ft=550MHz. What do you mean by distorted.