Hi all, indeed this is very interesting, can this buffer amplifier be used as a building block for a distribution amplifier for the 10 MHz signal of a thunderbolt? I remember having seen on the list a similar version but with european transistors (like the ubiquitous bc548/bc558?) that are very common here, but I can't remember when it was to surf the list archives in the right time-period. Anyone? best regards
Francesco IZ8DWF On 12/9/09, Ed Palmer <[email protected]> wrote: > I was thinking that I might be reinventing the wheel by designing a buffer > amp. You guys have almost built the entire car! Thanks again for the > ideas. It'll take me a while to get it built and tested. > > Ed > > Bruce Griffiths wrote: > > > John Miles wrote: > > > > > > > > > > > > > > > > > If it helps I can send you some LTSpice schematics so that you can > > > > > simulate the circuit for yourself. > > > > > The breadboards behave as predicted by the simulations at 10MHz. > > > > > > > > > > John Miles has done some preliminary phase noise measurements on his > > > > > version. > > > > > > > > > > The transformers are wound on binocular ferrite cores. > > > > > I used some 14mm (long) cores intended for 40MHz to 220MHz (I had > some) > > > > > operation in my breadboard which works well at 5MHz and 10Mhz. > > > > > > > > > > > > > > You can also use an off-the-shelf Mini-Circuits transformer for > low-power > > > > applications. The T13-1 was the one I tried. I'll stick some of > > > > the plots > > > > up on the web later tonight if possible. > > > > > > > > > > > See http://www.ke5fx.com/norton.htm for measurements > and connection details > > > of the copy of Bruce's amp that I added to my 5061A. > > > > > > -- john, KE5FX > > > > > > > > > > > Note the LED I used in the schematic was merely for simulation purposes > (ie LTSpice had a model for it). > > A standard red or amber LED is just fine. > > > > Another point is the LTSpice LED model isn't particularly accurate for > simulating the effects of temperature variations. > > Does anyone knows of more accurate LTSpice compatible LED models? > > > > The LED model voltage drop increases with temperature even at low current, > whilst the voltage drop across a real LED at low currents decreases with > temperature. > > In practice the variation in the LED forward drop tracks the variation in > the pnp Vbe quite well. > > > > Bruce > > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
