Here is a handy gadget for test- ing of infrared (IR) based re- mote control transmitters used for TVs and VCRs etc. The IR signals from a remote control transmitter are sensed by the IR sensor module in the tester and its output at pin 2 goes low. This in turn switches on transistor T1 and causes LED1 to blink.
Published: January 5th, 2009
Here is a handy zener diode tester which tests zener diodes with breakdown voltages extending up to 120 volts. The main advantage of this circuit is that it works with a voltage as low as 6V DC and consumes less than 8 mA current.
Published: January 4th, 2009
Here is a circuit of an off-line telephone tester which does not require any telephone line for testing a telephone instrument. The circuit is so simple that it can be easily assembled even by a novice having very little knowledge of electronics.
Published: January 4th, 2009
The given circuit, when connected in parallel to a telephone, dis- plays the number dialled from the telephone set using the DTMF mode. This circuit can also show the number dialled from the phone of the called party.
Published: January 3rd, 2009
Many a times one needs an ex- tra telephone ringer in an ad- joining room to know if there is an incoming call. For example, if the telephone is installed in the drawing room you may need an extra ringer in the bedroom.
Published: January 3rd, 2009
Here is a teleremote circuit which enables switching on and off of appliances through telephone lines. It can be used to switch appliances from any distance, overcoming the limited range of infrared and radio remote controls.
Published: January 1st, 2009
Most of the CDROMS available have an Audio-Out Output to either plug in the headphones or connect it to an amplifier. This circuit enables one to use the CDROM as a stand alone Audio CD player without the computer.
Published: December 7th, 2008
This is a little circuit to connect your MD or DAT to your CD-ROM drive with standard optical cable.. Parts cost about 50 FIM. This circuit is tested by me with no problems with locking to signal. Sources were Creative Infra CDROM and Creative Labs AWE32 soundcard. Recording device was SHARP MS-200H Minidisc.
Published: October 17th, 2008
This EPROM Emulator was designed to compliment the EPROM Programmer (Mark 2). An EPROM Emulator can save a vast amount of time when developing software, compared to programming and erasing EPROMs.
Published: September 29th, 2008
These instructions will help you to replace the LCD screen and the screen inverter on a Toshiba Satellite P205 series laptops.
Published: September 14th, 2008
I had to replace the CPU cooling fan in this Toshiba Portege A100 laptop. At first glance this laptop looked like a Macintosh iBook computer. The laptop was completely white, very unusual color for Toshiba laptop in the USA.
Published: September 12th, 2008
These instructions will help you to remove and replace keyboards on various laptops. I will not be able to cover all models but you will get the idea. Steps for removing and replacing the keyboard are similar for most laptops.
Published: September 10th, 2008
Electricity is created when certain chemicals react together. We use chemically- made electricity to power many machines from flashlights to a watch or sometimes a car. Yes, there are cars that run on electricity! The devices that store electricity are called batteries. Electricity can also be used to produce chemical changes.
Published: November 25th, 2008
Adding some Sulfuric Acid as electrolyte will increase conductivity of water and creation of Hydrogen and Oxigen gases.
Published: November 25th, 2008
This simple batch heater is popular in many southern states where freezing is not a problem. It is used to preheat well water for a domestic hot water system, however it is not very efficient because of night heat loss.
Published: November 25th, 2008
Is it possible to break water? In a sense, that is what electrolysis does. Electrolysis uses electricity to split water into its two ingredients - hydrogen and oxygen. Try it out with a battery and a couple pencils.
Published: November 25th, 2008
Visible light from the sun turns into heat when it strikes the dark interior wall of the greenhouse. This heated air tends to rise and concentrate near the top of the greenhouse.
Published: November 25th, 2008
The term goldenrod is typically used to describe a color of paper - golden yellow. Certain brands of goldenrod paper contain a special dye that turns bright red in solutions that are basic like ammonia water or washing soda. The paper turns back yellow with an acid like vinegar or lemon juice.
Published: October 5th, 2008
