DS

More and more people are using a PC (conventional or notebook) to view films. The VGA output can be used to provide a matching ‘Ambilight’ effect for this. If you restrict your-self to a single RGB LED, you can also draw the power for this circuit from the VGA connector, along with the RGB signals.  The following pins of the 15-way VGA connector (three rows of five pins) are used for  this circuit:  Pin 1:  Red video signal Pin 2:  Green video signal Pin 3:  Blue video signal Pin 5:  GND Pin 9:  +5 V  The video signals for the red, green and  blue channels are available at the RGB out-puts. These signals have an amplitude of 1 to 1.35 V, and they output the screen imagery at the rate of dozens of frames per second. This produces the visible image on the screen. The circuit described here drives an RGB LED according to the average values of each of these three signals. Of course, this is not a full-fledged ‘Ambilight’ system, but the RGB ...

When you step out of your brightly-lit house  into the darkness, it takes a while for your  vision to adjust. A solution to this problem  is this outdoor light with automatic switch-off. As a bonus, it will also make it a little bit  easier to find the keyhole when returning  late at night. Often no mains neutral connection is avail-able at the point where the switch-off timer  is to be installed, which makes many circuit  arrangements impractical. However, the circuit here is designed to work in this situation. The design eschews bulky components such as transformers and the whole unit can  be built into a flush-mounted fitting. The circuit also features low quiescent current consumption. Outdoor Lighting Controller Circuit Diagram : The circuit is star ted by closing switch (or  pushbutton) S1. The lamp then immediately receives power via the bridge rectifier. The drop across diodes D5 to D10 is 4.2 V, which provides the power supply for t...

GDT’s are special type of gas filled tubes used for wide range of electronic/electrical circuits for providing protection against lightning and other power surges.  These tubes basically has two electrodes that are kept inside a gas filled closed envelope. In case of electronic applications, the container is mostly ceramic in nature. For high grade electrical applications military tubes are used. The electrical characteristics of this tubes depends on the pressure and composition of gas, and the distance between the two electrodes contained inside. The most commonly used gases in GDT’s are given below. 1) Hydrogen gases 2) Deuterium gases 3) Noble gases 4) Elemental vapors (metals and nonmetals) 5) Other gases 6) Insulating gases An image of a ceramic discharge tube is shown below. Take a look. There will be conduction inside the GDT’s due to ionization of gas molecules. Each GDT have a specific voltage and current rating. A simple lightning protector circuit is given below. Lighti...

When you step out of your brightly-lit house into the darkness, it takes a while for your vision to adjust. A solution to this problem is this outdoor light with automatic switch-off. As a bonus, it will also make it a little bit easier to find the keyhole when returning late at night. Often no mains neutral connection is avail-able at the point where the switch-off timer is to be installed, which makes many circuit arrangements impractical. However, the circuit here is designed to work in this situation. The design eschews bulky components such as transformers and the whole unit can be built into a flush-mounted fitting. The circuit also features low quiescent current consumption. The circuit is star ted by closing switch (or pushbutton) S1. The lamp then immediately receives power via the bridge rectifier. The drop across diodes D5 to D10 is 4.2 V, which provides the power supply for the delay circuit itself, built around the CD4060 binary counter. When the switch is opened the l...

Automatic TV Lighting Switch . The author is the happy owner of a television set with built-in Ambilight lighting in the living room. Unfortunately, the television set in  the bedroom lacks this feature. To make up for this, the author attached a small lamp to the wall to provide background lighting, This makes  watching television a good deal more enjoyable, but it ’s  not the ideal solution. Although the TV set can be  switched off with the remote  control, you still have to get out of bed to switch off the lamp. Circuit diagram : Automatic TV Lighting Switch Circuit Diagram Consequently, the author devised this automatic lighting switch that switches the background light on and off along with the T V set. The entire circuit is fitted in series with the mains cable of the TV set, so there’s no need to tinker with the set. It works as follows: R1 senses  the current drawn by the TV  set. It has a maximum value  of 50 mA in standby mode,  ri...

How to Build Outdoor Lighting Controller  Circuit. When you step out of your brightly-lit house  into the darkness, it takes a while for your  vision to adjust. A solution to this problem  is this outdoor light with automatic switch-off. As a bonus, it will also make it a little bit  easier to find the keyhole when returning  late at night. Often no mains neutral connection is avail-able at the point where the switch-off timer  is to be installed, which makes many circuit  arrangements impractical. However, the circuit here is designed to work in this situation. The design eschews bulky components such as transformers and the whole unit can  be built into a flush-mounted fitting. The circuit also features low quiescent current consumption. Outdoor Lighting Controller Circuit Diagram : The circuit is star ted by closing switch (or  pushbutton) S1. The lamp then immediately receives power via the bridge rectifier. The drop across diodes D5...

Before we describe how it's done, note that we recommend that the result be checked as having sufficient brightness for a stop & tail-light application. That's because the light output may be inadequate, depending on the tail-light lens and reflector assembly - so use any modified lamps with discretion! As shown, an additional diode (D1) and resistor (68W) provide power from the "tail" circuit. Alternatively, when the "stop" circuit is powered, the resistor is bypassed by D2, thus increasing the LED current and the light output. Circuit diagram: Modifications to the lamp assembly instructions are as follows: After soldering in the copper tube but before soldering the platform board to the bayonet lamp base, the three components inside the dotted box must be wired up inside the base. The anode leads of the diodes can be soldered directly into the contacts ("bumps") on the base (a fine file or glass paper may be needed to get a nice round shape)....