APPARATUS FOR MEASURING THE PSYCHOGALVANIC REFLEX

• US 3,841,316 A
• Filed: 02/26/1973
• Issued: 10/15/1974
• Est. Priority Date: 02/26/1973
• Status: Expired due to Term

• Current Assignee: Richard W. Meyer
• Original Assignee: Richard W. Meyer
• Inventors: Meyer, Richard W.
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Cohen, Lee S.
• Application Number:
  US05/335,809
• Time in Patent Office: 596 Days
• Field of Search: 128/2.1Z,2.1R,2.6R 273/1E 35/22 324/62R
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0533 Measuring galvanic skin response

Abstract

An electronic circuit for measuring the psychogalvanic reflex in human beings. Two finger electrodes are connected on adjacent fingers of a person'"'"''"'"'s hand. These electrodes are part of a resistance bridge circuit which uses a transistor as an unbalance gating device. A meter indicates the bridge voltage. This meter is nulled, or the circuit balanced, by adjustment of a variable resistor. So long as the person to whom the electrodes are attached receives no exciting stimuli, the circuit will remain balanced. Should the person answer a question untruthfully, this will create sufficient stimulus to trigger the psychogalvanic reflex, thus creating a circuit unbalance due to the decrease in apparent skin resistance. This unbalance will appear as an increased transistor collector current and will cause a meter deflection, thus indicating that a particular response was not truthful.

Claims

1. Apparatus having automatic meter overload protection for measuring the psychogalvanic reflex in human beings comprising, in combination:

a. a voltage source;

b. a switch connected in series with said voltage source;

c. a first resistor connected in parallel with said voltage source;

d. a second resistor, connected in series with said first resistor and connected to said voltage source;

e. a third resistor connected in parallel with said first and second resistors;

f. a variable resistor, connected in series with said third resistor, having a variable voltage tap connection;

g. a transistor with a base, a collector and an emitter, having its base connected to said variable voltage tap and its emitter connected to said voltage source;

h. a fourth resistor, connected in parallel with said first and second resistors and connected to the collector of said transistor;

i. a galvanometer type meter connected between the collector of said transistor and a circuit node location between said first and second resistors;

j. a fifth resistor connected between the collector of said transistor and said meter; and

k. electrode means for engaging the skin of a person to sense the resistance of the skin of said person and connected to form a resistance in parallel with said third resistor.