This low-cost timer can be used to introduce a delay of one minute to two hours. When the time is up, music will sound.

This daylight control light uses the photo resistor (LDR) as the daylight sensor and 25 high-brightness white LEDs. LED with an independent resistor in series in each row.

The cold current of the halogen lamp is low and it is easy to burn out. The internal rapid heating of the bulb melts the filament and shortens the bulb life. The circuit here allows the halogen lamp to soft start, thereby extending the life of the halogen lamp.

This is a simple circuit that can generate three different tones. You can use it as a call bell, anti-theft alarm or any other security alarm.

The circuit described here protects your appliances from damage due to low voltage when switched on (for example, AC motors). Keep it in the standby state, and do not supply power to the load after power-on, and can only turn on the load manually. This can prevent damage to the device and turn it on when power is restored.

This is a simple green LED flashlight built around a 555 timer IC (IC1) and powered by a 3V battery pack.

This multi-function flash includes three parts: flash, sound and light display and white LED flashlight.

A simple low-power inverter circuit is described here, which converts 12V DC to 230V AC. It can be used to power very light loads such as night lights and cordless phones, but it can be modified into a powerful inverter by adding more MOSFETs. This circuit has two-stage battery chargers with cut-off function, the battery level indicator and the inverter charging circuit are built around IC1 (LM317).

Since the anti-theft alarm of the laser torch usually only works in the dark, this remote photoelectric alarm can work during the day and can also warn you of intruder compounds in a large area. The alarm includes a laser transmitter and receiver unit, which should be installed on the opposite pillar of the entrance door. Once someone enters and interrupts the laser beam, the beam falls on the receiver, and the buzzer in the circuit sounds an alarm.

This infrared object counter can be installed at the entrance door, and the total number of people can be counted no matter where it is. For example, it can be used in train stations or bus stops to calculate daily or weekly passenger flow.