The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 25, 1978
Filed:
Apr. 29, 1977
Donald Stephen Nemcek, Sr, Roselle, IL (US);
Cole-Parmer Instrument Company, Chicago, IL (US);
Abstract
An electrometric apparatus, which uses a measuring device that provides a high impedance dc signal which varies in accordance with the variable to be measured. The dc signal is amplified by at least one amplifier means and the amplified signal is applied to an indicating means which indicates the amplitude of the amplified dc signal. The supply voltage for the amplifier means is provided by a dc power supply means connected through a regulating means to positive and negative supply busses and for the amplifier means. The regulating means includes a transistor having its emitter-collector circuit connected in series between the power supply means and the positive supply bus of the amplifier means. A resistor and a Zener diode are connected in series and the series combination is shunt connected between the supply busses. A pair of series connected resistors are shunt connected between the supply busses. A programmable operational amplifier has one input connected to the junction between the resistor and the Zener diode and the other input connected to the junction between the series connected resistors. The output of the programmable operational amplifier is connected to the base of the transistor.