Warning display circuit of the electric shutter for camera

Claim 1

A warning display device in an electric shutter of a camera having an exposure time control circuit for determining the exposure time of the electric shutter in dependence upon at least the brightness of an object being photographed and developing an exposure time signal in dependence upon said brightness; said warning display device including a warning display circuit comprising a first stage circuit (N) having an over exposure indicating element (14) and a single transistor (20) for driving said over exposure indicating element; a second stage circuit (M) and a third stage circuit (L); each of said second stage circuit and said third stage circuit having a corresponding display inidicating element (15, 16), a driving transistor (21, 22) for driving the corresponding display indicating element, an RC integrating circuit (26, 30, 27, 31) directly connected to the base of the last-mentioned driving transistor (21, 22) and a clamping transistor for clamping the corresponding driving transistor upon said warning display circuit receiving an exposure time signal from said exposure time control circuit, diode means (34, 35, 36, 37, 38) connected for feedback among the first, second and third stages of the warning display circuit and between the warning display circuit and the exposure time control circuit for preventing signals energizing one stage display indicating element from energizing the display indicating elements of the other stages; means including a switch for controlling operation of said exposure time control circuit; connections from said exposure time control circuit for applying said exposure time signal to said warning display circuit; and each RC circuit developing a corresponding independent reference signal for comparison with said exposure time signal for control of operation of a corresponding display indicating element.