Time Delay circuit using Triac and 555 timer

This Time delay Circuit using Triac and 555 Timer is very useful when we want to activate or switch on, appliances or devices that works on alternating current (AC), after a preset time.

This darkness detector circuit beeps when the light drops below a certain level.

The main elements of this circuit are the 555 integrated circuit, working as an astable multivibrator and an LDR which is used as darkness sensor.

Police Style Strobe Light Circuit.

This circuit shows the familiar lights which are used on police cars. It uses a 555 timer as a clock for the 4017B decade counter, two transistors and twelve LEDs

Electronic Doorbell Circuit using a 555 timer and a CD4017 decade counter

This electronic doorbell circuit gives us all the possibility to change the tone of each of the 10 musical notes that the circuit can have. This means we can create our own sound sequence.

How to make a car temperature alarm?
This car temperature alarm check the car engine temperature and warns us, by means of a sound signal, when the temperature exceeds a seted value

DC motor speed controller circuit using 555

This simple DC motor speed controller circuit, works with 12 volts and controls a DC motor using the 555 integrated circuit.

Car Burglar Alarm using two 555 timers

This is a simple Car Burglar Alarm circuit that uses a dual contact relay and two 555 timers, each of them working as a monostable multivibrator.

The alarm will activate the car horn, approximately 5 seconds after either door is opened and has not been properly closed.

This simple humidity sensor circuit using a 555 timer, shows us the humidity level that a ground under test has. To achieve the goal, a couple of probes are used.

These probes are placed on the ground to be tested.

This ON-OFF Switch circuit using a 555 timer is simple, useful and easy to implement.

This circuit has many applications on places where it is necessary to activate and deactivate (connect and disconnect) an electrical or electronic device.

555 IC Tester Circuit (PCB)

This 555 IC tester circuit, allows us to make sure that this integrated circuit works properly. This same test can be achieved by operating the 555 as astable multivibrator, but this test does not allow
to observe its operation in detail.

12 VDC to -12 VDC converter circuit with a 555 IC.

This 12 VDC to -12 VDC converter circuit gives -12VDC (negative 12 volts) from a power source of + 12VDC (positive 12 volts), with very few components.

Refrigerator door alarm circuit with two 555 timers

This refrigerator door alarm circuit alerts you when the door has been left open. Very important, because the power consumption increases when this happends. It uses the popular 555 timer IC