In:
Japanese Journal of Applied Physics, IOP Publishing, Vol. 33, No. 5R ( 1994-05-01), p. 2757-
Abstract:
In order to improve the response speed of a very low level dc current amplifier, we propose a novel method in which a photocoupler, instead of a high resistor (10 10 Ω), is employed for the negative feedback circuit. In this paper, it is shown experimentally that with the proper use of positive feedback, the rise time t r of 10 µs is obtained for this circuit at the current sensitivity of 10 pA. In comparison, the t r with the use of the high resistor with the shielding plate is 120 µs. (Here, the current sensitivity is the minimum measurable input signal current that produces an output signal voltage of a very low level dc current amplifier equal to its output noise voltage, or that leads to a signal-to-noise ratio of unity.)
Type of Medium:
Online Resource
ISSN:
0021-4922
,
1347-4065
DOI:
10.1143/JJAP.33.2757
Language:
Unknown
Publisher:
IOP Publishing
Publication Date:
1994
detail.hit.zdb_id:
218223-3
detail.hit.zdb_id:
797294-5
detail.hit.zdb_id:
2006801-3
detail.hit.zdb_id:
797295-7
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