build an automatic school bell timer circuit

Capacitance Meter Using 555 Oscillator circuit

The frequency formula of a 555 oscillator is well-known. For given resistors and capacitors, the frequency can be calculated using a specific formula derived from mathematical principles. The 555 timer IC is widely used in various applications, including oscillators, timers, and...

Simple 555 Timer Monostable Circuit

The two circuits below illustrate using the 555 timer to close a relay for a predetermined amount of time by pressing a momentary N/O push button. The circuit on the left can be used for long time periods where the...

Water Activated Alarm

The circuit utilizes a 555 timer configured as an astable oscillator and is powered by the emitter current of the BC109C transistor. In dry conditions, the transistor does not receive bias current and remains fully off. When the probes become...

Capacitance Meter

The 555 timer IC serves as the core component of the circuit, tasked with charging an unknown capacitor (Cx) to a predetermined voltage. Following this, the capacitor discharges into a meter circuit, which measures the current flowing through a 47-ohm...

555 zinc-manganese batteries reduction charger circuit

The circuit utilizes a 555 timer as the core component to create an astable multivibrator. The oscillation period T is given by the formula T = 0.693 (R1 + 2R2) C1, which corresponds to an oscillation frequency of approximately 100...

12V power inverter using 555 timer circuit

This 12V power inverter circuit can be utilized to power small devices that require 240 volts. It is particularly advantageous for operating 240-volt appliances using a 12-volt car battery. Unlike typical feedback oscillator inverters, this design employs a 555 timer...

200W Lamp Flasher with 555 timer

200W Lamp Flasher is used to flash lamps, bulbs and halogen lamp to give your product that attracting look. More: Input supply - 6 ~ 12 VDC Output - upto 200 W lamp / bulb load Optically isolated Mains supply Onboard preset to...

Neon Desk lamp

The circuit is based on IC1, which is a 555 timer IC in astable mode. It will power a 6 inch 4 Watt fluorescent tube off a 12 volt supply, consuming 300 mA. It may also be powered by a...

Multi Switch Controlled Relay

A Multi Switch Controlled Relay circuit is utilized to manage home appliances, featuring a circuit diagram that outlines the application of a multi switch-controlled relay using a single integrated circuit (IC) for various control functions. The Multi Switch Controlled Relay circuit...