LONG DELAY TIMING SYSTEM

• US 3,577,168 A
• Filed: 06/21/1968
• Issued: 05/04/1971
• Est. Priority Date: 06/21/1968
• Status: Expired due to Term

• Current Assignee: Godfrey R. Gauld, William J. Tuten
• Original Assignee: Godfrey R. Gauld, William J. Tuten
• Inventors: Tuten, William J., Gauld, Godfrey R.
• Application Number:
  US04/739,011
• Time in Patent Office: 1,047 Days
• US Class Current: 368/114
• CPC Class Codes: H01H 43/32 with timing of actuation of contacts due to electrolytic processes; with timing of actuation of contacts due to chemical processes
• CPC Class Codes: H03K 3/40 by the use, as active elements, of electrochemical cells

Abstract

The disclosure illustrates a longterm timing system comprising a battery coupled to an electrochemical cell through a pulsing circuit. The electrochemical cell is of the type that requires current flow above a minimum value to enable proper operation. The pulses from the pulsing circuit have a peak substantially greater than the minimum permissible current level but the pulses are substantially spaced in time. The resultant average current flow is then low enough so that the time at which the impedance of the electrochemical cell changes is greatly increased.

Claims

1. A timing system comprising:

a source of direct current;

an electrochemical cell including an anode having a given amount of material plated thereof and a cathode on which the material is plated in response to current flow through said electrochemical cell, all of said material being plated on the cathode at a point in time after a predetermined quantity of current flow, thereby causing an abrupt substantial increase in impedance, said electrochemical cell requiring a current level thereacross above a minimum safe operating current to prevent formation of whiskers and short circuiting between the anode and the cathode;

means for converting the output of said direct current source into a series of current pulses, said pulses having peak values substantially greater than said minimum safe operating current and a substantial and equal predetermined time spacing therebeTween;

means for applying said pulses to said cell whereby the quantity of current flow required to increase the impedance of said cell is attained after a substantial time period; and

means for detecting the increase in impedance of said electrochemical cell for generating an output signal.

2. A timing system as in claim 1 wherein:

said current pulse means comprises means for establishing a predetermined ratio between the duration between adjacent pulses and the width thereof, whereby the time period increase for said timing system is proportional to said ratio.

3. A timing system as in claim 2 wherein:

said current pulse means comprises means for adjustably varying the ratio between the duration between adjacent pulses and the pulse width for varying the time period after which said impedance increase takes place.

4. A timing system as in claim 1 wherein:

said electrochemical cell has a volume generally proportional to the quantity of current flow required to plate material on the cathode, said current pulse means being adapted to generate current pulses sufficiently short in duration and sufficiently spaced so that the resultant average current value is a relatively small value whereby the size of said cell may be minimized and the time necessary to plate the predetermined amount of material on the anode is minimized.

5. A timing system as in claim 4 wherein said current pulse means requires a relatively low expenditure of power whereby the timing system may be used for extremely long time periods.

6. A timing system as in claim 5 wherein said current pulse means comprises a relaxation oscillator.

7. Apparatus as in claim 1 wherein said detecting means is a voltage detector.