Touch controlled voltage-divider device

• US 3,895,288 A
• Filed: 09/04/1973
• Issued: 07/15/1975
• Est. Priority Date: 09/04/1973
• Status: Expired due to Term

• Current Assignee: Spectra Symbol Corp. (Zebra Technologies Corporation)
• Original Assignee: Stephen H. Lampen, William E. Hearn
• Inventors: Lampen, Stephen H., Hearn, William E.
• Primary Examiner(s): Goldberg, Gerald
• Application Number:
  US05/394,161
• Time in Patent Office: 679 Days
• Field of Search: 338/69,119 323/94R,95,17 320/1
• US Class Current: 323/304
• CPC Class Codes: H01C 10/00 Adjustable resistors
• CPC Class Codes: Y10S 323/904 Touch systems

Abstract

A voltage divider device capable of providing any voltage in a preselected range of voltages, which voltage may be set by a touch of the finger is disclosed. The device includes a control element without frictional contacts and a voltage storage circuit controlled by the control element. A circuit including the device is described and embodiments of the device providing a visual indication of the setting of the device are disclosed.

Claims

1. A voltage-divider device comprising:

a. an elongated resistive surface;

b. an elongated conductive surface arranged in close spaced, substantially coextensive relationship with said resistive surface;

c. means for selectively establishing galvanic contact between each of a plurality of points along the length of said resistive surface and the point corresponding thereto along the length of said conductive surface by a touch of the finger;

d. a voltage source connected to opposite ends of said elongated resistive surface for establishing a voltage gradient along said resistive surface with respect to ground;

e. a voltage storage means;

f. means for detecting the presence of a voltage on said conductive surface with respect to ground including a first resistance connected between said conductive surface and ground and a voltage comparator circuit adapted to produce an electrical output when any voltage with respect to ground is present on said conductive surface; and

g. means for changing the voltage stored with respect to ground by said voltage storage means including a normally open electrical switch means connected between said conductive surface and said voltage storage means, said switch means being closed by said electrical output of said voltage comparator circuit to establish electrical connection between said conductive surface and said voltage storage means.

2. A voltage-divider device as claimed in claim 1 wherein said voltage storage means includes capacitance to ground and wherein said switch means is connected to said conductive surface through a diode, a second resistance being connected to ground from the junction between said switch means and said diode.

3. A voltage-divider device as claimed in claim 1 wherein said voltage storage means comprises a digital network adapted to maintain the last voltage applied thereto with respect to ground.

4. A voltage-divider device as claimed in claim 1 wherein an electronic buffer circuit is interposed between said conductive surface and said voltage storage means.

5. A voltage-divider device as claimed in claim 4 wherein a second electronic buffer circuit is electrically connected to said voltage storage means to provide an output corresponding to the voltage stored, said output of said second electronic buffer circuit controlling a voltage controlled amplifier circuit.

6. A voltage-divider device as claimed in claim 5 wherein a circuit providing a controlled amount of positive feedback is connected between the output of said second electronic buffer circuit and the input of said voltage storage means.

7. A voltage-divider device as claimed in claim 1 wherein one end of said elongated resistive surface is connected to ground.

8. A voltage-divider device is claimed in claim 5 wherein An elongated voltage responsive visual indication means is physically associated with said elongated resistive surface and electrically connected to said output of said second electronic buffer circuit to provide a visual indication of the point along the length of said resistive surface at which galvanic contact was last established.

9. A voltage-divider device as claimed in claim 1 wherein said normally open switch means of said means for changing the voltage stored with respect to ground comprises an electronic device having its electron emitter connected to said conductive surface, its electron collector connected to said voltage storage means and its control electrode connected to said output of said voltage comparator circuit.

10. A voltage-divider device as claimed in claim 3 wherein said normally open switch means comprises a first gate means and a second gate means, said voltage comparator circuit being connected to one of the inputs of said first gate means and said conductive surface being connected to one of the inputs of said second gate means, a digital clock being connected to the other input of said first gate means and the output of said first gate means being connected to the other input of said second gate means.