By Topic

Limitations of transistor DC amplifiers

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Hoffait, A.H. ; Solvay and Company, Brussels, Belgium ; Thornton, R.D.

This paper considers the important mechanisms contributing to drift in low-level differential dc amplifiers using matched-pair silicon transistors operated at low collector currents. It is shown theoretically and experimentally that thermally induced drift and sensitivity to power-supply variation are both reduced substantially by operating the two transistors with equal VBEinstead of with equal collector currents. Moreover, by intentionally unbalancing the passive components in the circuit, it is shown to be possible, in principle, to achieve a self-compensating operation with almost perfect cancellation of drift. Experimentally, for a source resistance of 400Ω, it was not difficult to achieve equivalent input drifts of the order of 0.05 µv per °C, 0.2 µv for a 1 per cent variation in supply voltage and 0.3 µv drift over a three day period. The ultimate limitation appeared to be 1/f noise which was on the order of 0.5 µv peak to peak.

Published in:

Proceedings of the IEEE  (Volume:52 ,  Issue: 2 )