We are all trying to reduce energy costs and CO2 emissions by choosing modern alternatives to incandescent lamps. Here are some lighting charts to help you select the best lamp for your situation. Since the decline of incandescent lamps there have been many alternatives made available based on fluorescent tubes bent in many ways to condense a long tube into a confined space.
Continue reading “Lighting Charts – Which Lamp Do I Need?”Morse Code was devised by Samuel Finley Breese Morse, an American artist and inventor, in the 19th century. It is made up of a series of dots and dashes when written down.
When spoken a dot is pronounced “dit” if it is the final element of a character, else it’s pronounced “di”, and a dash is pronounced “dah”. e.g. “C” [ — · — · ] = “dah-di-dah-dit”.
If Morse Code is transmitted as a beam of light then the transmitting light often has a shutter in front of it which is opened by means of a lever to let the light out. Historically this is because the persistence of electric lights is too long if they are turned on and off by electrical means.
If Morse Code is transmitted as a radio signal, or current down a wire, then the signal is controlled by a special electrical switch known as a Morse Key or Telegraph Key. In its simple form this is an ON/OFF switch, but in its more complex form it is a changeover switch. With the changeover switch in one position it sends a series of dots and in the other position it sends a series of dashes. The timing of these is electronically generated. The operator leaves the key in the central position (the default) when not transmitting and moves the key from side to side to send the necessary dots and dashes while listening to his output on headphones. By this means the operator can send a fast signal with fewer movements of the wrist.
When transmitted as a radio carrier wave, light or electrical current a dot is a short burst of radio carrier wave, light or current, and a dash as a burst of radio carrier wave, light or current with a period three times as long as a dot.
The period between a dot/dash and the next dot/dash within the same character is equal to the period of a dot.
The period between characters is equal to the period of a dash.
The period between words is the same as seven dots.
Ref. http://en.wikipedia.org/wiki/Morse_code#Development_and_history
