Circuit for indicating the condition of the battery in a photographic camera

• US 4,338,596 A
• Filed: 01/14/1980
• Issued: 07/06/1982
• Est. Priority Date: 04/19/1977
• Status: Expired due to Term

• Current Assignee: Agfa-Gevaert AG (Agfa-Gevaert N.V.)
• Original Assignee: Agfa-Gevaert AG (Agfa-Gevaert N.V.)
• Inventors: Borowski, Kurt, Huber, Theodor, Egger, Gerhard
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): Myer, Daniel
• Application Number:
  US06/112,562
• Time in Patent Office: 904 Days
• Field of Search: 340/636, 340/663, 340/691, 324/433, 324/436, 320/48
• US Class Current: 340/636.15
• CPC Class Codes: G03B 17/18 Signals indicating condition of a camera member or suitability of light indicating depth of field G03B13/30
• CPC Class Codes: G03B 43/00 Testing correct operation of photographic apparatus or parts thereof

Abstract

When the battery voltage is sufficient, and not nearing the point of insufficiency, a light-emitting diode is steadily illuminated. As the battery voltage decreases, the steady component of illumination decreases and also, when the decrease has proceeded to a certain extent, a superimposed pulsating component of illumination is introduced, causing the illuminated LED to begin to flicker, informing the user that the battery voltage is nearing insufficient values. As battery voltage drops further, the steady component of illumination ceases altogether, and the flicker converts to on-off blinking, indicating that the battery voltage is at the verge of an insufficient value. When the battery voltage drops fruther, the LED ceases to be illuminated. During part or all of the flicker phase, and/or during part or all of the blinking phase, the frequency of the pulsating component of illumination progressively increases with decreasing battery voltage, to create an effect of increasing urgency. In addition, or alternatively, at a certain point during pulsating illumination the frequency of the pulsating component is abruptly increased, likewise to create an effect of urgency.

Claims

1. A battery monitoring circuit for monitoring voltage of a battery and indicating such voltage to a user, comprising:

an indicator;

a transistor connected to the battery and connected in series with the indicator, to permit the indicator to generate a first continuous indication;

an astable multivibrator connected to the battery and connected in series with the indicator to permit the indicator to generate a discontinuous indication and a second continuous indication which is different from said first continuous indication; and

a selector connected to the battery, the transistor and the astable multivibrator and cooperating therewith in a manner that the indicator generates the first continuous indication when the battery voltage is in a safe range, the indicator generates the different second continuous indication when the battery voltage is in a marginal range, and the indicator generates the discontinuous indication when the battery voltage is in an unacceptable range, said astable multivibrator being connected in parallel to the main-electrode path of said transistor so that the lower value of the second continuous indication is equal to the lowest permissible battery voltage value.

2. The circuit defined in claim 1, wherein the astable multivibrator oscillates with a frequency which varies with voltage of the battery.

3. The circuit defined in claim 2, wherein the frequency increases as the battery voltage decreases.

4. The circuit defined in claims 1, or 3, wherein the indicator is a light-emitting semiconductor, wherein the first continuous indication is a constant emission of light of an essentially constant intensity, wherein the second continuous indication is a constant emission of light of a periodically varying intensity, and wherein the discontinuous indication is a periodic emission of light in a discontinuous series of pulses.