US 4,053,799 A · Voltage memory device

Abstract

The invention discloses an analog voltage memory device comprising an operational amplifier, a reed relay, a capacitor and a MOSFET which are so interconnected to each other that the input voltage applied to the operational amplifier is compared with the output voltage from the MOSFET applied to the noninverting input terminal of the operational amplifier, thereby providing the output voltage whose magnitude follows the level of the input voltage and holds a desired level thereof for a long time. The analog voltage memory device may further include an additional operational amplifier which compares the input voltage with the output voltage and closes the reed relay only when the input voltage is higher than the output voltage so that the source follower output voltage from the MOSFET follows only the peak of the input voltage and remains at the level of this peak. The analog memory device in accordance with the present invention will revolutionize the art of analog memory used, for instance, for storing a monitor level, a tuning level, a finally adjusted value or a peak value of the output from an analog measurement instrument.

Claims7

Dependent claims

An analog voltage memory device comprising

a. an input resistor,
b. a reed relay having one contact connected to one terminal of said input resistor,
c. a MOSFET having the gate thereof connected to the other contact of said reed relay,
d. a nonpolarized capacitor interconnected between the gate of said MOSFET and ground,
e. an output resistor interconnected between the source of said MOSFET and ground,
f. a first operational amplifier having a noninverting input terminal, an inverting input terminal, and an output terminal, said source being connected to said inverting input terminal, means for applying an input signal to said noninverting input terminal, said output terminal of said first operational amplifier being connected to the other terminal of said input resistor, and
g. a second operational amplifier having an inverting input terminal connected to said source, a noninverting input terminal, means for applying said input signal to said noninverting input terminal, and an output terminal coupled to a coil of said reed relay for energizing said relay only when said input voltage is higher than the voltage at said source, whereby said analog voltage memory device provides an output voltage across said output resistor whose magnitude follows the peak of said input voltage.

4 more elements

Dependencies are inferred from the claim text.

Voltage memory device

Life of this patent

Voltage memory device

Life of this patent

Abstract

Claims7