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Browse Prior Art Database

Transistor Differential Current or Volt Meter

IP.com Disclosure Number: IPCOM000098874D
Original Publication Date: 1958-Aug-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Watkins, RV: AUTHOR

Abstract

In the illustrated current or volt meter circuit diode D(1) provides proper operating voltage for the transistor TR-1. R1 is calculated to protect the meter when the transistor is saturated. Diode D3 prevents excessive reverse voltage swing at the base of the transistor TR-1. Resistor R(2) and potentiometer Pl provide bias current for the transistor which is biased for center scale meter reading. Diode D(2) provides a reference voltage to which I(2)R(4) is compared to obtain the current differential.

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Transistor Differential Current or Volt Meter

In the illustrated current or volt meter circuit diode D(1) provides proper operating voltage for the transistor TR-1. R1 is calculated to protect the meter when the transistor is saturated. Diode D3 prevents excessive reverse voltage swing at the base of the transistor TR-1. Resistor R(2) and potentiometer Pl provide bias current for the transistor which is biased for center scale meter reading. Diode D(2) provides a reference voltage to which I(2)R(4) is compared to obtain the current differential.

The sensitivity of this circuit depends upon the meter sensitivity and the current gain of the transistor amplifier. A multi-stage feedback stabilized amplifier may be used to compensate for variations in transistors parameters and supply voltages.

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