Emergency Light chain scheme can be viewed directly on the image above
|: 33 Ohm|
: 470 Omh
: 470 uF/16v
: switch (push on push off)
: BC 160 or BC 143
: 4,5 volt 200 mA
: lamp 2,5 volt
: NiCd 2x1,25 volt 2-4 Ah
Series of automatic lighting unit is very simple. Voltage electricity from the net PLN revealed by transformer Tr1 and change in DC with half-wave system by dioda D1 and capacitor C1.
Next portion 6 Volt DC is used to fill the 2 Ni-Cad Battery through R1 and D2 with a continuous flow of about 100 mA (charging current to a safe a Ni-Cad battery 2 Ah).
reverse bias between the base of emitor transistors T1 obtained from the voltage fall on the D2 will make transistors T1 does not work so that lamp will be off. When voltage net PLN suppressed, T1 base transistors will be biased flow through R2, transistors T1 will work and lamp on.
When the voltage net PLN entry, transistors T1 will does not work, the lamp will be off and the battery charged through R1 and D2