Circuit Diagram Knowledge

Very fast acoustic electronic flash releases as used by professional photographers and in quick motion film apparatus for action filming are  beyond the means of most amateur photographers.
Simpler acoustic releases are normally not fast enough: a picture of a burst balloon is not very interesting; one of a burst balloon is! lf you want to film events which happen in a split second and which make a sound at the same time, the circuit described is just right for you. To make possible the filming of events which are over before the sound reaches the camera, we have designed a simple light barrier through which, for instance, a drop of water can be made to fall (see below). The level ( at which the electronic flash fires is then preset by either·Pl. (acoustical) or P2 (light barrier). The output is connected to  the timing input of the electronic flash unit. The power supply is no problem: as the current consumption of the circuit is only about 30 mA, a 9 V battery will last quite a time. First a few words about the circuit. IC1, an audio amplifier lC, is used as microphone amplifier with a maximum amplification of 200. IC2 is used here as a monostable multivibrator. lf a pulse caused by a noise input arrives at pin 2 of IC2, it triggers the multivibrator. The output of the multivibrator (at pin 3) triggers thyristor Th1 which in turn triggers the. thyristor in the electronic flash unit. Where the light barrier is used,the part of the circuit to the left of terminals 1