What is a flash ?: Images that are obtained by transferring images of objects to light-sensitive films are called photographs. In photography, a sufficient light source is required to clearly transfer the image of the object to the photosensitive material. Here, the artificial light generators used during the photo shoot are called flash .
The flashes use two electrode lamps that are vented and placed mutually in a glass body filled with inert gases. The lamp operates with voltages of about 300-400 V. In addition, a third electrode (auxiliary electrode) is placed in the body to allow the element to start emitting light.
This electrode extends through the tube and ends close to the electrodes on the edge. When the voltage is applied to the lamp, the discharge starts and a high light is emitted due to the effect of the electron movement between the electrodes.
High light emitting flashes work as 1/500 – 1/5 s when taking pictures. The high DC voltage, which enables the lamp to operate in flashes, is produced with circuits similar to converters and filled in capacitors and the load of the capacitor is applied to the electrodes of the flash lamp as soon as the shutter button in the camera is pressed.
n the given circuit, the DC voltage applied to the input with a simple oscillator circuit with transistor is converted to a high frequency AC and applied to the primary windings of the transformer. Variable currents passing through the primary of the TR1 transformer create a high-value AC in the secondary winding. The high voltage is obtained by the high voltage diodes from the secondary
and the high DC required to operate the flash is obtained. When the neon lamp emits light, it is clear that the flash is ready to operate.
As the primary current of the TR3 transformer will be reduced to zero at very high speed by touching the shutter button, a high value voltage is generated in the secondary winding of this element. This voltage affects the middle electrode (auxiliary electrode) of the flash lamp causing ionization. The ionization of the gas in the tube initiates the passage of current between the two ends on the edges and the passing current generates a high light.
