3 ms·
I think actually the hard part in the 50s might be the current amplifier but I'm not au fait enough with the tech of the time to know if nanoamp amplifiers were
by xyzzy123 10y ago
I think actually the hard part in the 50s might be the current amplifier but I'm not au fait enough with the tech of the time to know if nanoamp amplifiers were easy. I think it's not so different from radio but would be interested in an educated opinion.
- Animats 10y agoThat's a good point. A very high gain DC amplifier with low noise would have been hard then. A STM needs to sense about 1na at 0.1V, which means a series resistance of about 100 megohms. Vacuum tube voltmeters of the 1940s and 1950s era were getting close, with about 10 megohms input resistance.[1] Sensing 0.1V through 100 megohms with tubes doesn't seem out of reach. High RF gains are easier to get than DC gains; you can filter out everything but the frequency of interest and reduce noise. That's basically how radios amplify weak signals. But I don't think you can run an STM on RF. [1] http://www.tubebooks.org/Books/rider_VTVM.pdf http://www.tubebooks.org/Books/rider_VTVM.pdf