G-switch timer – Vern Knowles

The timer is built using four small inexpensive CMOS integrated circuits. This allows it to run on just 3V from two small AAA batteries. U1 is a 74HC688 8-bit equality comparator. It compares the switch settings to the counter output and will set pin U1-19 low when they match. The actual counter is U2. It is a 74HC4060 14-stage binary ripple counter with built-in oscillator.

The G-switch itself uses a cantilevered metal bar that pivots down as the rocket accelerates upward. The metal bar actuates a small micro-switch that triggers a digital counter to begin the timing sequence. The timer is designed so that it will not start unless the micro-switch has been activated for a duration of at least 0.5 seconds.

G-switch timer - Vern Knowles

G-switch timer – Vern Knowles – The timer was built using a small prototyping circuit board and point-to-point wiring.

U3 is a 74HC74 D-type flip-flop that is used as part of the triggering logic. U3-12 will be low when the counter matches the switch settings. Consequently, on the next oscillator clock edge from U2-9 the flip-flop output at U3-9 will go low. This is the event that activates the 2N4403 transistor that fires the flash bulb.

Thaikits – Electronic Kits for Learning

A group of test engineers in Thailand who worked in an Electronic factory more than 12 years have started a small business to sell electronic projects and electronic kits worldwide in 2007.

CH012 Transistor Curve Tracer adapter XY Oscilloscopes 2 ranges Bias

Thaikits - Electronic Kits for Learning

Some interesting kits are HHO High Frequency PWM DC Motor Speed Controller 30A, CH018 Cycling Timer 1.5 -180 minutes ON-OFF 12VDC/30A Heavy Duty 110V/240VAC, CH024 ICL8038 Function Generator Sine Triagle Square wave 0.5Hz-100kHz.

5/16 Moo 18 ,Bueng Kham Phroi,Lam Luk Ka, Pathum Thani 12150, Thailand

The Art of Electronics – Paul Horowitz Winfield Hill

The Art of Electronics covers the full range of subjects normally treated in electronics books, as well as a rich complement of important but neglected topics.

The Art of Electronics, by Paul Horowitz and Winfield Hill

The book covers many areas of circuit design, from basic DC voltage, current, and resistance, to active filters and oscillators, to digital electronics, including microprocessors and digital bus interfacing. It also includes discussions of such often-neglected areas as high-frequency, high-speed design techniques and low-power applications.

The Art of Electronics - Paul Horowitz Winfield Hill

Learning the Art of Electronics – A Hands-On Lab Course

This introduction to circuit design is unusual in several respects. First, it offers not just explanations, but a full course. Each of the twenty-five sessions begins with a discussion of a particular sort of circuit followed by the chance to try it out and see how it actually behaves.

The Art of Electronics – Paul Horowitz Winfield Hill

The book includes many example circuits. In addition to having examples of good circuits, it also has examples of bad ideas, with discussions of what makes the good designs good and the bad ones bad. It can be described as a cross between a textbook and reference manual, though without the chapter-end questions and exercises which are often found in textbooks.

Paul Horowitz is a Research Professor of Physics and of Electrical Engineering at Harvard University, where in 1974 he originated the Laboratory Electronics course from which emerged The Art of Electronics.

Winfield Hill is by inclination an electronics circuit-design guru. After dropping out of the Chemical Physics graduate program at Harvard University.