Simple Flashlight LED Torch Circuit using CD4049 IC

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You must have seen many LED flashlights in the market, mostly using white LEDs as they provide perfect brightness and light. LEDs are excellent for applications subject to frequent on-off cycling, unlike fluorescent lamps that burn out faster when cycled frequently or HID lamps that require a long time before restarting. You can quickly dim or strobe them. So in this tutorial, we are going to design a simple “LED Torch Circuit using CD4049 IC”

The LED lights up promptly, and a typical LED red light reaches full illumination in milliseconds. These mostly fail by fading over time rather than the abrupt burn-out of incandescent bulbs.

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Hardware Components

The following components are required to make LED Torch Circuit

S.No	Component	Value	Qty
1.	Breadboard	–	1
2.	Connecting Wires	–	1
3.	Buffer/Inverter IC	CD4049	1
4.	Diode	1N4007	2
5.	Resistor	6.7K	1
6.	Ceramic Capacitor	0.1uF, 220uF	1, 2
7.	Battery	9v	1
8.	LED	5mm	3

CD4049 Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of CD4049

LED Torch Circuit

Working Explanation

We supply 5V DC voltage to the circuit. In the circuit, you arrange the resistor R1 and capacitor C1 with two NOT gates to make the oscillator circuit. The remaining 4 NOT gates connected in parallel form a buffer and twice the input voltage. As you turn on the supply capacitor, C2 starts charging, via a buffer made by four not gates, until the peak of the input voltage (5V). And now C2 acts as a second power source of 5V, so with the D1 and D2 forward biased, capacitor C3 charges with combined voltages of the power supply and the capacitor C2. Therefore, with the combined voltage of both, the capacitor C3 charges up to almost 10V.

The output voltage is enough to glow three white LEDs, and we have a Bright LED Torch.