Telephone Lamp Circuit -  Here is a White LED Lamp that turns on when the telephone rings. The cool white light helps to locate the phone in darkness and also helps to note the message or telephone number. The lamp remains on for three minutes then turns off. The telephone lamp circuit is powered by a 9 volt PP3 battery and connected to the telephone. . .  [Circuit Posted by D Mohankumar]

Temperature to Frequency Converter -  This circuit directly converts temperature to digital data. In this case, a thermistor sensor biases the RSET pin. The LTC1799 frequency output is predictable, although nonlinear. The inverse RSET vs frequency relationship combines with the thermistor’s nonlinear characteristic to give Figure 8’s data. The curve is nonlinear, . . .  [Linear Technology App Note, Mar 26th 2010]

Temperature-to-Frequency Converter -  Precision oscillator structure uses SCR effect to discharge integration capacitor. A temperature dependent device (LM134) effects the integrator trip point to form a variable interval. An output transistor detects the reset action and forms a logic pulse. . . .  [Linear Technology App Note, Jun 21, 2011]

Termination Schemes & Design Guidelines for 3.3V Lvpecl Driver -  Application Note # 07) 3. . .  [Pericom Semiconductor]

Termination supply tracks one-half core voltage -  04/27/00 EDN Design Idea   Modern µPs typically require core voltages of 2 to 3V. They also require "termination" voltages that, for best performance, should equal half the core voltage. The problem is, core voltages vary among CPUs, and some systems even . . .  [by Chester Simpson, National Semiconductor, Santa Clara, CA]

Test Continuity -  This circuit will detect low resistances and high resistances to produce a tone from the speaker. It will detect up to 200k and the circuit automatically turns off when the probes are not used. . . .  [No designer name given]

Test Continuity -  This circuit senses only dead shorts on a populated board. It will not ring through or damage components. It shuts off when not in use. It was first published in Electronics magazine, June 21, 1979, page 145. . .  [Designed by Andrew R. Morris]

Test Continuity -  Starting with a 9 volt supply, when the probes are shortcircuited there is a 8. 2 volt drop across the zener diode Z1 leaving a maximum of 0. 8 volt across R1. Application of Ohms' Law showse. . . .  [Tony van Roon's circuit]

Test Continuity -  This is another invaluable piece of test equipment for digital work. It has been designed by us to cater for a particular application. . . .  [Collin Mitchell's web site]

Test Human Reaction Time with the 555 IC -  With this simple circuit that is built with the 555 IC you can test human reaction time. You can find out how fast do you react by trying to catch a flashing LED. How does the human reaction tester works? When S1 is ON the circuit acts as a astable multivibrator and the LED is lit for about 0. 1 second and is flashing every 1. 5. . .  [Circuit posted by Popescu Marian]

Test timer -  The output goes high for a fixed period of time when power to a unit under test (UUT) is turned on, and again when it is turned off. It was used with a magnetic sensor to test the spin-up and spin-down time of a gyroscope. . . .  [Designed by Andrew R. Morris]

Tester Continuity -  Among the essentials for circuit design and prototyping is the continuity tester, a simple device which provides an audible indication when a sufficiently low resistance is applied between its input probes. This version has a feature which automatically turns off the tester after about two minutes, thereby saving the 9 volt battery from inadvertent discharge. The tester produces a high-pitch tone when less than 10 ohms is placed between the input probes. The 10 ohm threshold is a convenient value that indicates hard-wired paths, but excludes indications for circuit paths through most components. In addition, the amount of current presented to the circuit by this. . .  [Designed by Arthur Harrison]

The 555 Timer -  (spice design) . . .  [Rick (last name not given)]

The Kicker -  A simple circuit that momentarily closes a pair of contacts at long intervals. Useful when you need to kick something into action every few hours or days. . . .  [Circuit Design by Burton Lang]

The Science of Timekeeping -  Application Note. . .  [Aligent]

The Solid-State Tesla Coil -  Nikola Tesla is considered by some to be the greatest inventor of our modern electrical age, and many experts consider him to be the true father of radio. However, today he is best remembered for his fascinating wireless power-transmission experiments, using his famous Tesla Coil. The high-frequency air-core, oscillating Tesla Coil is just as exciting today as it was back in 1899, when he used it to successfully transmit electrical energy over 25 miles, without wires, to light a large number of incandescent lamps. The Tesla Coil is ideal for demonstrating and exploring the unusual phenomena that occur with high-frequency high-voltage energy. . . .  [Rewritten by Tony van Roon (VA3AVR)]'

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