Remote Flash Unit

More or less every camera has its own flash unit as a built-in part.  But the built-in flash unit is obviously very small and also the flash light will not cover a long distance. In this case, additional heavy duty flash unit/s are very much required for the proper photography. Using of additional flash unit/s are much advantageous for the photographers to eliminate or minimize the shadow behind the object. Therefore, Remote Flash Unit/s could provide the above advantage. But, the question is how to operate the additional flash unit/s at the same time with the camera flash unit, as it is very much important to flash the additional flash units in synchronizing with the camera flash unit.

Now-a days the Remote Flash Units are available in the market that operate either with synchronizing cable or the remote flash unit to operate with its own battery supply. Here we are discussing regarding a Remote Flash unit that will operate without battery.

The heart of the Remote Flash Unit is “LIGHT ACTIVATED SILICON CONTROLLER RECTIFIER” (LASCR). The Gate is tripped by light entering through a small lens built in to the Top Cap. The output (Anode & Cathode) of the LASCR is to be connected with a Sync Cable of about 6” long to connect with the additional Heavy Duty Flash Unit.

WORKING PRINCIPAL: At the time shuttering of the camera the built-in Flash Unit flashes immediately to the object and surrounding areas. The same light falls instantly to the LASCR of the Remote Flash Unit and it activated the sync connector of the Remote Flash Gun thus the Remote Flash Gun flashes immediately. The approximate time delay is about 5 mili second.

When using this device, place the LASCR Lens facing towards the main camera unit so that, the flash light from the camera flash gun will fall directly to the lens of the LASCR.

No reset is needed as the voltage at the flash’s sync terminals falls below the LASCR’s holding voltage when the flash is fired and thereby turning off the LASCR.

Bill of material and Circuit Schematic

Electronic Circuits – Simplified