Simple Little Nightlight Circuit Diagram

Here we describe a very simple, economical and light-weight automatic nightlight that runs on 230V AC mains and can be used as a deluxe gizmo in the sleeping room of your kids. The arrangement proposed by the author is shown in Fig. 1.

Circuit diagram for the nightlight is shown in Fig. 2. It is built around three resistors (R1 through R3), two light-emitting diodes (LED1 and LED2), a light-dependent resistor (LDR1), a BC548 transistor (T1) and a capacitor (C1). Here LED1 is blue and LED2 is RGB with rainbow effect.

  Little Nightlight Circuit Diagram

The circuit operates off 230V AC, consuming very little current. The generic 5mm LDR drives the rainbow LED (LED2) through npn transistor T1. Series resistor R3 (150-ohm) limits the current through LED2. The sensor circuit ensures that the rainbow light switches on when it gets dark and off when there is ambient light. If desired, you can change its detection threshold by varying the value of 47-kilo-ohm resistor R2.

Resistor R1 (100-kilo-ohm), 1N4007 diode D1, and 4.7µF, 16V electrolytic capacitor C1 are used to down-convert the 230V AC input supply to a very low-value DC supply. The 5mm blue LED (LED1) not only works as an always-on pilot lamp but also keeps the voltage across buffer capacitor C1 close to around 3V. When the circuit is in active state (that is, in darkness), LED1 also produces a waving effect in tune with the current consumption of the entire circuitry.

The rainbow LED is a low-cost flashing LED with inbuilt driver chip. When power is applied, it flashes red, blue and green colours each for several seconds, then it slowly mixes these colours together to form other colours. Fig. 3 shows the author’s lab experiments.

Construction and testing

An actual-size PCB layout for the little nightlight is shown in Fig. 4 and its components layout in Fig. 5. After assembling the circuit, enclose it in a suitable box.

 PCB layout of little nightlight

 Components side of the PCB

Construction and testing

An actual-size PCB layout for the little nightlight is shown in Fig. 4 and its components layout in Fig. 5. After assembling the circuit, enclose it in a suitable box.

Fix CON1 so that you can connect 230V AC easily. Connect LDR1 such that light from LED1 and LED2 doesn’t fall on it. After proper assembly and connections, your little nightlight circuit is ready to use. Proposed enclosure is shown in Fig. 6.

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DC / AC Voltage Inverter 12v for 110 - 220V Circuit Diagram

This is the DC / AC Voltage Inverter 12v for 110 - 220V Simple and Powerful. Here is from a voltage inverter 12 Volts DC to 110 or 220 Volts AC. It is capable of generating a 50 or 60 Hz AC voltage (AC) with a square wave, which can feed most electronic equipment in a home.

Equipment with some types of motors will not work well with this voltage inverter and may even be damaged, so use it only on equipment that does not require AC power or that is not as sensitive to the type of wave.

Voltage Inverter

This circuit is very simple, uses less than 12 component to build a DC to AC voltage inverter.

 DC / AC Voltage Inverter 12v for 110 - 220V Circuit Diagram

The principle of this circuit is to generate a frequency between 50 and 60Hz through the integrated circuit CD 4074, this signal coming from pins 10 and 11, which are in opposite phases of 180º, these 50 Hertz pulses are taken to the IRFZ MOSFET transistors 44 that amplify these pulses giving them more current, after amplifying the pulse it is taken to the transformer generating high voltage in the secondary of 220Volts or 110 Volts AC depending on the used transformer.

The output waveform of the inverter is square and is improved almost to a "modified" wave with a Cn filter of 220nF, in my opinion the output is a square wave cropped, well away from being a sine wave.

The integrated circuit used. the CD4047 is a TTL integrated circuit that operates both in monostable mode and in steady mode. Below the CD4047 pinout.

The oscillator components of the CD4047, R1 / C1, are a capacitor (between pins 1 and 3) and a resistor (between pins 2 and 3), they will determine the output pulse width in monostable mode, and the output frequency in astable mode.

To increase the output current (power) a high current battery, more MOSFETS transistors in parallel and a compatible transformer should be used. For example, to obtain 240W output the battery used is at least 20A.

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