Lights and Display Board CircuitsOscillators Circuit Diagrams



The images obtained by transferring the images of objects to the light-sensitive films optically are called photographs. In photography , enough light source is needed to transmit the cismin image clearly to the light-sensitive material . Here, the artificial light generators used during photography are called flash.

In flashes, two-electrode lamps are used which are air-displaced and interposed in a glass body filled with inert gases . The lamp operates with voltages of around 300-400 V. In the meantime, a third electrode (auxiliary electrode) is placed in the body so that the element can start emitting light.

This electrode extends along the tube and ends near the electrodes at the edge. When the discharge is initiated when the voltage is applied to the lamp, a high light is produced due to the effect of the electron movement between the electrodes.

The flashes that emit a high light work for 1/500 – 1/5 s when the photo is taken. The high DC voltage that allows the lamp to operate in flashes is produced by circuits similar to converters and charged to the capacitors, and when the pull-down button (shutter) is pressed on the camera, the charge of the capacitor is applied to the electrodes of the flash lamp.

The DC voltage applied to the input is applied to the primary coil of the transformer by turning it into a high frequency AC with the transistor simple oscillator circuit. The variable currents passing through the primary of the TR1 transformer form a high-valued AC in the secondary winding. By high voltage diodes taken from Sekonder, high
DC is obtained which is required to operate the flash . When the neon lamp lights up, it turns out the flash is ready for operation.

When the shutter button is touched, a high-value voltage is generated in the secondary winding of the TR3 transformer because the primary current of the TR3 transformer is rapidly reduced to zero . This voltage causes ionization by affecting the middle electrode (auxiliary electrode) of the flash lamp. The ionization of the gas in the tube initiates the flow of current through the two edges at the edges, and the passing current brings a high light intensity.


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