Multiple Flash Unit
By Jock Orr
This unit is intended for situations where it is
inconvenient to use the ordinary flash lighting techniques. In effect, it is a lightweight studio
lighting outfit which enables the cave photographer to position his lights as
and where he wants them. The general
arrangement is shown on the next page and the Central Box circuit diagram, also
on the next page, is quite easy to follow.
The electrical components may be obtained from any amateur radio shop, and the flash bulb sockets from a photographic dealer. The reflectors are made from scrap headlamp reflectors, and although the parabolic form of the reflector is designed to cast a beam, this can be altered to cause the spread of light by trial positioning of the flashbulb socket before final fixing.
Apart from the major expense of the cables, the cost of the
unit amounts to about £3, and while a description of its construction may be of
general interest, it will only be of a particular interest to the serious cave
photographer who will recognise immediately the technical advantages to be
gained form this equipment.
N2/P2
N1/P1
|
OUTPUT
Switches
UP 25v fires 1 to 3 Flash.
Switches
DOWN 50v fires 4 to 6 Flash.
|
Switch
A Double Pole
Switches
B & C Instrument switches
| |
R1
Resistor 3,300 OHM
R2
Resistor 5,600 OHM
| |
C1
Capacitor (electrolyte) 25-30v. D.C. 100mf
| |
C2
Capacitor (electrolyte) 50-60v. D.C. 100mf
| |
S.W.1 Miniature Press Switch.
S.W.2 Miniature Press Switch
| |
L.1 Miniature Signal Bulb
L.2 Miniature Signal Bulb
|
The control box consists of two tobacco tins soldered
together with cut-outs for mounting the components shown in the circuit
diagrams. All sockets and plugs are
standard 2 pin, flat body, ex-Woolworths. All electrical connections should be soldered. The cable and flashbulb circuits are
SERIES. Operating instructions and
suggested layouts will appear in a later issue of the B.B.