Light Flasher Circuits   Page 7
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Last Updated on: Sunday, July 27, 2008 07:40 PM
 

Circuits Designed by Dave Johnson, P.E. :
SIMPLE NITROGEN SPARK GENERATOR Nitrogen or air sparks are very powerful light sources that produce flashes that last only a few nanoseconds. This line-powered circuit generates a continuous series of very small sparks across electrodes with a 0.05-inch gap.

Safety Flasher:  This circuit alternately flashes two high-brightness LEDs as a safety measure during jogging or walking. The LED’s can be mounted on clothing or a belt. The circuit draws a precisely controlled 10mA in order to conserve battery life. Also, the battery voltage can drop to the LED voltage plus about .5 volts before there is a noticeable change in performance.   The LEDs actually act like voltage regulators. Because the blue LED has a higher drop voltage, it will dim rapidly and then go out first (about 3 volts) with decreasing battery voltage. The yellow LED will keep blinking unaffected to about 2 volts of battery voltage. Also due to the higher voltage drop of the blue LED, the blue LED is on for less time than the yellow LED at normal battery voltage.   Designed by Andrew R. Morris  (added 6/06)

Sequential LED Flasher:  for10 LEDs (added 4/02)

Simple colour organ:  (electronic circuit added 4/05)

Simple flashing light circuit 1:  (electronic circuit added 4/05)

Simple flashing light circuit 2:  (electronic circuit added 4/05)

Simple flashing light circuit 3:  (electronic circuit added 4/05)

Simplified white LED flasher operates from one cell:  05/26/05 EDN Design Ideas  / (added 1/06)  The white-LED flasher in Figure 1 offers an alternative approach to a previously published idea (Reference 1). Targeting use in portable appliances and products powered by a single cell, this circuit flashes an LED to provide a highly visible warning signal—for example, to indicate power on, battery low, or another eye-catching visual signal. However, white LEDs typically present a forward-voltage drop of 3 to 5V. Given that a single cell's end-of-life output voltage decreases to 1V, flashing a white LED from such a low voltage demands special circuit techniques. The circuit in Figure 1 exploits the low-voltage capabilities of Fairchild's universally configurable two-input NC7SV57 logic gate. The NC7SV57 operates from a supply voltage as low as 0.9V, a key requirement for single-cell applications....

Simulate the Gyralite (dual flashing headlights).:  (electronic circuit added 4/05)

Single cell flashes White LED:  12/11/03 EDN Design Ideas  /  (added 1/05)  Many portable appliances and other products that must operate from a single cell are restricted to working at very low voltages. It is thus difficult to drive white LEDs that typically have a forward voltage of 3 to 5V. The ability to flash the LED with a supply voltage as low as 1V presents additional complications....

Solid state blinker for automotive applications:  AN454 that limits the output current slew rate (di / dt) during the switching edges....  (app note added 6/06)

Solid Stateher has Short Circuit Protection:  1/16/97 EDN-Design Ideas / (added 4/02)   -Switches an inductive or resistive grounded load using a bootstrapped n-channel power MOSFET and features short-circuit, reverse-polarity, and transient-input-voltage-spike protection, operates from18 to30-Volt DC, and the circuit can handle as much as approximately10A with proper heat sinking of the FET

Special Effects from a Six Pack:  Four channel Sequencer to Analog Dimmers and idea how to couple relay to the circuit (added 4/02)

Strange LED sequencer:  This bizzare but simple PWM circuit fades from LED to LED. This deceptively simple sequencer actually pulse width modulates the LEDs as it fades from one LED to the next. Bulbs will last much longer when driven in this gentle manner; add FETs or transistors to the outputs if you wish to drive bulbs. You can reconfigure the capacitors from a delta configuration to a star configuration, or you can remove one of them entirely and the circuit will still function. Use high efficiency red LEDs for best results. This circuit was inspired by the BEAM sequencer circuits on the web. I simply reversed the roles of the resistors-capacitors and 'floated' the capacitors to create this monstrosity which incidentally chirps out RF interference as it hobbles along. (added 2/05)

Strobe Controller:  Simple controller for professional stroboscopes, adjust the flash rate in1.15 Hz range (added 4/02)

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