T&L Publications

Signetics also sent out a data sheet for a DED (Darkness Emitting Diode) at the same time. That must have been a less popular part than the WOM (Write Only Memory) since I haven't seen that data sheet reprinted.

One caution in using the AVR. The In System Programmer uses four dedicated pins on the chip to load the program. After programming, these can be used as I/O lines. The programming mode is entered when the reset line is active when power is applied. If this pin is programmed as an output pin, the chi...

2 quarts x .946 liters/qt x 1000 mL/L x 1 gm/mL = 1,892 gm Specific heat of water: @25 C = 4.1796 joule/gm C @100 C =4.2160 joule/gm C average specific heat = 4.198 J/gm C To raise water from 25 C to 100 C: 75 C x 1,892 gm x 4.198 J/gm C = 5.957 x 10^5 J Specific heat of vaporization = 539.55 cal/gm...

Hello Dean, The Leach web site (www.leachintl.com) has the Leach catalog. The 065D relay uses the following designations: X1, X2=Coil Connections A1=pole #1 NO A2=pole #1 COM A3=pole #1 NC B1=pole #2 NO B2=pole #2 COM B3=pole #2 NC The KD relay uses these designations: X1, X2=Coil Connections A1=pol...

About 1980, Westinghouse showed a demonstration at a trade show using induction heating of a section of iron pipe as a source of hot air to pop popcorn. The induction heater used a couple of their newly introduced bipolar transistors, which were rated somewhere around 400 volts at 100 amps (the tran...

Conversion between 2 phase and 3 phase power can be done with a transformer connection called a "Scott T". I suspect that most power distribution was done with 3 phase power, and that individual users would convert it to 2 phase power if it was needed. I have seen several reprints of books...

An RCA tube manual for 1940 listed the 5U4. An early data sheet for the 5U4 was also dated 1940. It could be a few years older than this.

The original use may have been console radio receivers with high powered adio sections (such as push-pull 6L6s) or small transmitter power supplies.

Edison's lamp used a filament made of split bamboo that was converted to carbon by charring, probably by heating in an inert atmosphere. This doesn't take much technolgy. This was used for arounf 20 years, so it was a practical solution. It was replaced by the tungsten filament, which required a sub...

There is no need to run the LED in the QRD1114 at 50 mA. That is a maximum rating. The data sheet gives the device characteristics for an LED current of 20 mA and this is probably as good a value as any. At this point, the output curent of the phototransistor is a minimum of 1 mA with the specified ...

It would be especially beneficial if Kudzu vine could be processed into ethanol. This grows wild in the southeastern United States without the use of irrigation or fertilizer. It grows quite rapidly, so it might be possible to harvest several crops per year from the same land.

The trick might be to use the microprocessor to load an external six bit shift register in parallel. This register is then shifted at a higher clock rate to get the serial video signal. The processor only has to load five bits, since the space between charaters will always be the same, and can be ha...

If you assume an audible signal is about a millivolt in a set of 2000 ohm earphones, the signal power is about 1/2 nanowatt. A 50 kilowatt broadcast station would be able to supply the power for 10^14 receivers if the transmission was 100 percent efficient. Mathematically, that is a finite number. F...

The NTSC signal does have a substantial DC component. Separating this from the the DC supply mignt be tricky, since DC variations in the supply voltage would be interpreted as changes in brightness. The choke would have to have substantial reactance at 60 Hz, since the NTSC signal has strong spectra...

According to the Atmel AT09S2313 data sheet, both parts are 10 Mhz parts in a 20 pin DIP package. The AT90S2313-10PC is a commercial temperature range part (0 to 70 centigrade). The AT90S2313-10PI is an industrial part (-40 to 86 centigrade). Except for the temperature range, both parts appear to be...

Hello Al, The patent on this soldering iron is number 6,646,228 (assigned to Hyperion Innovations). It can be downloaded from the US Patent Office (www.uspto.gov). The tips are described as graphite separated by a mica insulator. Hyperion Innovations has also obtained design patents for specific des...