NE555 Simple Nightlight

Chip 555 series (NE555, SE555, NA555, SA555 and their analogues) is an affordable and cheap timer - a device for generating pulses with specific temporal characteristics. Many simple devices can be built on the basis of these microcircuits - from motor speed regulator to time relay and voltage regulator. The article will discuss one of the most common applications of the NE555 - a dimmer for adjusting the brightness of LEDs, which can be adapted for a homemade night light.

Part 1. Electronics.

The device diagram is presented below:
 A simple night light on a microcircuit
Diodes VD1 and VD2 can take any, for example 1N4148. R1 adjusts the brightness of the VD3-VD9 LEDs. You can take a variable resistor combined with a switch, this option will look good in styling for old kerosene lamps, in which the brightness of the flame was controlled by a special pen.If you do not plan to change the brightness of the lamp, then any trimmer resistor set to the appropriate value will do. The C3 capacitor may be of a lower rating, or it may not be at all - the circuit will still start, but in this case the dimmer will emit a barely audible squeak. Board assembly:
Simple nightlight on a microcircuit
 A simple night light on a microcircuit
LEDs are divided into two groups of 4 and 3 LEDs. Of course, there may be more or less of them, but it should be remembered that the choice of the transistor VT1 depends on the number and power of the LEDs. For a small number of low-power LEDs, like mine, any NPN transistor will fit, even KT315 or its foreign counterparts. For a more “voracious” load (for example, LED strip and high-power LEDs), it’s better to choose an EB13005 type transistor, which can be found in any energy-saving lamp, or the widespread field-effect transistor IRFZ44N. NE555 has a wide supply voltage range, therefore For the circuit, you can use any suitable power supply (for example from a laptop) or charging from the phone.It is not recommended to power the dimmer from batteries or accumulators, since the scheme of switching on LEDs with limiting resistors does not presuppose a sufficiently high efficiency, and the power source will quickly be discharged. The voltage will depend on the number of LEDs and the resistance of their current-limiting resistors. If you know how it is calculated, go boldly to the next part, if not, take a few minutes to read the short guide. So, the resistance is calculated by the formula: R = Upt - Ucv / Icv, & nbsp , where R is the resistance of a current-limiting resistor, Upt is the supply voltage of the circuit, Uc is the voltage drop across the LED, Ic is the power supply voltage of the LED. The values ​​of Ucb and Icv are different depending on the color and power of the LEDs, it should be specified in the documentation for the specific model. If there is no documentation (which is the norm for the overwhelming majority of Chinese products), then you can use the averaged values ​​from the table:

Color and Type

Voltage Drop on the LED (Volt)

LED power supply (ampere)

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