Abstract In an electronic flash unit circuit arrangement there is provided an electronic flash tube with a shunt circuit lying in parallel to said tube and becoming conductive in dependence on the quantity of light reflected from the subject to be photographed and then short-circuiting said flash tube. This shunt circuit comprises a series connection of an electronic switch element controllable by a control circuit operated by said reflected light quantity and of one or several auxiliary capacitors which take up the excess energy from the storage capacitor whose charge energizes said flash tube. This storage capacitor may be short-circuited by means of a switch or it may be used for improving the energy balance of the entire flash circuit arrangement.
In an electronic flash unit which includes in combination a flash tube, a first capacitor for energizing the flash tube, a light sensitive control circuit having an output dependent on the portion of the light emission of the flash tube reflected from The subject to be photographed, and quenching means including a normally disabled controllable electronic gate connected in shunt with the flash tube, the control circuit being coupled to the control gate to enable the gate when the output of the control circuit has reached a predetermined value for bypassing the remaining energy of the first capacitor from the flash tube, an improved construction for the quenching means which comprises: a second capacitor; and means for connecting the second capacitor in series with the gate across the flash tube; power supply means including a battery for energizing the first capacitor, and means for applying the voltage across the second capacitor to the battery for charging the battery.
Claim 2
Dependent Claim
158 words
In an electronic flash unit which includes in combination a flash tube, a first capacitor for energizing the flash tube, a light sensitive control circuit having an output dependent on the portion of the light emission of the flash tube reflected from The subject to be photographed, and quenching means including a normally disabled controllable electronic gate connected in shunt with the flash tube, the control circuit being coupled to the control gate to enable the gate when the output of the control circuit has reached a predetermined value for bypassing the remaining energy of the first capacitor from the flash tube, an improved construction for the quenching means which comprises: a second capacitor; and means for connecting the second capacitor in series with the gate across the flash tube; power supply means including a battery for energizing the first capacitor, and means for applying the voltage across the second capacitor to the battery for charging the battery.