Project: Christmas light power strip

Thread Starter


Joined Apr 27, 2007
This is a power strip that supplies intermitent power to christmas light series. It is a more reliable alternative than using a intermitent light bulb to control a series, since a stuck intermitent bulb can cause others fail due to continuous activity. The power strip has two pairs of sockets, each one supplying power in an alternating sequence. The power strip is fused, and each socket pair can supply power up to 570W.
This project requires some skills and it is not for beginners. It uses the mains power, with inerent hazards added to it.

List of components:
C1 – 150μF electrolytic capacitor (50V);
C2 – 100nF tantalum electr. capacitor (25V);
C3 – 3,3μF tantalum electr. capacitor (25V);
C4 – 10nF ceramic capacitor (10% tol., 25V);
D – 1N4001 rectifier diode;
DB – DF005 rectifier bridge;
F – 2,5A fast fuse;
IC1 – LM78L12 voltage regulator;
IC2 – 555 timer (LM555, NE555 ou equiv.);
R1 – 39KΩ carbon resistor (5%tol., 1/8W);
R2 – 390KΩ carbon resistor (5%tol., 1/8W);
Rl – SPDT 12V relay (200mW, 3A);
S – 3A SPST switch;
T – Transformer 230V~ 15V~ 1,2VA.