A Circuit that fades an LED on and off.
Overview
These two circuits make a LED fade on and off. The first circuit charges a 100u and the transistor amplifies the current entering the 100u and delivers 100 times this value to the LED via the collector-emitter pins. The circuit needs 9v for operation since pin 2 of the 555 detects 2/3 Vcc before changing the state of the output so we only have a maximum of 5.5v via a 470R resistor to illuminate the LED.
Schematic
Overview
These two circuits make a LED fade on and off. The first circuit charges a 100u and the transistor amplifies the current entering the 100u and delivers 100 times this value to the LED via the collector-emitter pins. The circuit needs 9v for operation since pin 2 of the 555 detects 2/3 Vcc before changing the state of the output so we only have a maximum of 5.5v via a 470R resistor to illuminate the LED.
Schematic
1x - NE555 Bipolar Timer
1x - LED (Red) 1x - 470 Resistor (1/4W)
1x - 33K Resistor (1/4W)
1x - 100µF Electrolytic Capacitor (16V)
1x - BC547 NPN Transistor
1x - 9V Voltage Battery
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