Page 30 Switch Electronic Circuits

Switch Circuits
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Last Updated: November 30, 2017 01:32 PM

Circuits Designed by Dave Johnson, P.E. :

Water Seepage Monitor - A while back I received a request from a company who needed a water seepage detector. They wanted a device that ran on 24vac and detected water using a fully isolated circuit. They wanted a circuit which switched off 24vac to a load when water was detected . . . [Circuit by Dave Johnson P.E., 01/16/11]

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Water Activated Relay (Marin Lukas) - In his circuit Marin has used two transistors wired as a high gain compound pair. Transistor T1 may be a 2N2222A and T2 a BC108. The current gain will be the product of each transistors beta, which will be a minimum of 140 x 110 or 15400. The power supply used can be any voltage from 4.5to 15 volts, . . . [Designer is Marin Lukas]

Water Seepage Monitor - A while back I received a request from a company who needed a water seepage detector. They wanted a device that ran on 24vac and detected water using a fully isolated circuit. They wanted a circuit which switched off 24vac to a load when water was detected . . . [Circuit by Dave Johnson P.E., 01/16/11]

Waterproof Bathroom Switch - The object of this circuit is turn the domestic lighting on and off in complete safety in a room with very high humidity. A detector, flush-mounted into the wall, detects the magnetic field variations. must register on this site. . . [Published in Elecktor July/Aug, 2010]

Whistle on Whistle Off - This CMOS toggle flip flop circuit has an addition of2bandpass filters and condenser microphone so the relay can be toggled by whistling at it. . . . [Bill Bowden's website]

Whistle Responder - Beeps when hears your whistle; A gadget suitable for key-holders, games etc. . . [Flavio Dellepiane's web site]

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Whistle Switch - The whistle switch allows you to turn on, or off, an appliance by whistling at it. I originally built the whistle switch in 1974. Do not attempt to duplicate it from the schematic below, but instead, understand the functions and duplicate these functions with more modern components. . . . [by Michael Ellis]

Whistler: Electronic Trainer/Coach - This device makes it possible to generate beeps at chosen regular time intervals for timing track race training. Each time interval is indicated by a beep, and the end of a performance test is indicated by a double beep. Two types of test are allowedmust register on this site. . . [Published in Elecktor July/Aug, 2010]

White LED driver backlights LCD and keypad - 11/13/03 EDN Design Idea Designers widely use white LEDs to backlight color LCDs and keypads in handheld devices, such as cell phones, MP3 players, GPS navigators, and PDAs. Their spectrum and brightness represent near-ideal light sources. One possible con. . . [by Fabien Franc, Catalyst Semiconductor, Sunnyvale, CA]

Winning the Battle Against Latchup in CMOS Analog Switches - Scroll to find this circuit. . . [Analog Devices-Analog Dialogue by Redmond, Catherine]

Wireless bicycle brake light - 04/17/14 EDN Design Idea The TI LDC1000 senses bike wheel rotation and controls a stop light. My submission video shows the new Texas Instrument's LDC1000 attached to the rear wheel fork of a bicycle, where it senses the spokes as the wheel rotates. This proof-of-concept demonstration shows how perfect this sensor is for my goal of an improved bicycle brake light that has many advantages. I'm passionate about getting this invention completed and on the market as soon as possible, where it can help prevent some of the many injuries and deaths to the hundreds of millions of the world's bicyclists each year. . . [by John Craig]

XY Keypad uses µC's Serial Port - 10/10/96 EDN Design Idea Interfacing an X-Y keypad to a microcontroller usually uses a parallel port of 8 bits or more. But with the circuit shown in Figure 1, a more efficient interface using a microcontroller's serial port reduces the number of connect. . . [by James Mears, National Semiconductor, Tacoma, WA]

Zener level-shifter drives high-side switch - 06/16/2014 EDN Design Idea simplify a high-side driver by replacing a transistor with a Zener diode. Microcontrollers, the heart of all modern electronic gadgets, are increasingly powered with sub-5V power supplies. This complicates the control of external loads powered by higher voltages. . . [by Dhananjay Gadre & Nidhi Sharma]

Zero-Delay Bus Switches - Application Note # 001. . . [Pericom Semiconductor]

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