Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: Negative Resistance Posted: Sun Sep 16, 2007 9:23 am
Fri Aug 11, 2006 6:07 am
I'm trying to synthesize a negative resistance to add to a circuit. As
far as I know there are three popular ways of doing so:
1. Using a device with negative resistance
characteristics (e.g. Tunnel Diode).
2. Using a configuration of OpAmps with feedback that gives a negative
resistance when seen from the input.
3. Using a configuration of BJTs, ot FETs.
It is the third method
that I'm interested in since I'm working at a somewhat high frequency and I need to be able to integrate the
resulting circuit on an IC. I'm specifically interested in making a negative resistance using MOSFETs. I did read
a couple of papers that talked about the subject but it was quite general, with no reference to biasing or methods
of tuning. While I was able to sucessfully simulate a negative resistance using two MOSFETs, the resulting
resistance was quite large (tens of Mega Ohms) and it was unstable when put in a larger circuit.
resistance I need is S-type, in the range of tens of Ohms. Can anyone point me to where I can get more info on