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TWILIGHT SWITCH

TWILIGHT SWITCH

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  IDEA ELECTRONIC PROJECT

Circuit description:
The mount allows the automatic ignition of a lamp 220 V, when darkness settled.
Initially, an oscillator 555 whose working frequency is set by R2, R3 and C3. The load being C3 through R2 and R3 and discharges through R3. But when the photo-resistance Ph (A LDR) is illuminated, its resistance is low. The adjustable resistor RA1 is set for the "Reset" input (4) 555 to be low enough to block the oscillator circuit. So, nothing comes in 3 and triac T remains blocked. Floor lamp is off!
In the darkness, Ph increases strength and allows the oscillation of the output 555. The slots are differentiated by C5 and R5 to give T1 output pulses sent the trigger T. This leads: Lamp lights.
For free tilting, a hysteresis is established, with recovery, D2 and C5, the output signal and reinjection, assayed by RA2 of the voltage obtained on the reset input 4.
Please note that the LDR should not "see" the light from the lamp Ch, under penalty of malfunctions.

NOMENCLATURE

R1 100 R
R2 150 KR
R3 2.2 KR
R4 12 KR
R5 12 KR
R6 1 MR
R7 47 R
R8 12 KR
Paj1 220 KR Hor
Paj2 470 KR Hor
C1 100 nF 400
C2 100 .MF Rad
C3 15 nF LCC
C4 15 nF LCC
C5 1 MF Rad
C6 470 nF LCC
D1 a D3 1N4148
D4 zener/7.5 
T1 TUP
ICI 555 
clips pile 9V
TRIAC 6A/400V 
1 support 8br 
1 bornler 3p/CI 
1 LDR-12
1 PORTE FUSIBLE
1 FUSIBLE 6A
1 cordon secteur

Production . Settings

Warning, this assembly is powered directly from the mains with voltage reduced to 7.5 V, by Ci and the zener. The 555 should be a "CMOS".
Do not forget that the strap under 555. A terminal block facilitates implementation. Initially put Raj2 maximum resistance.
Set Raj1 for failover to the desired light transition. Then Raj2 adjust to a good net tripping.
IF Ph receives light from Ch, installation between oscillations.

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