9V Door Bell Chime Project

Integrator multiplies 555 delay

Long delay times can be derived from a 555 timer with reasonably sized capacitors if an integrator circuit is used.

Incandescent LED Circuit

This circuit when used with a 555 timer will cause light emitting diodes to turn on and off more slowly. This will make the LEDs appear similar to incandescent lamps.

Door-Chime Schematic

This is a circuit that could be used as a doorbell system like those that most homes have. From what I can tell, pressing the switch triggers the IC to oscillate and send electricity through the transistors to power the speaker. The IC type is not listed, but I am guessing that it is a 555 Timer.

IR Remote Control Extender Circuit (Mark 3)

IR appliances use pulses (control signals) sent over a modulated IR carrier wave. The carrier wave may be modulated at various frequencies, 36-38KHz being the most popular.Some Satellite receivers use even higher frequencies than this. The IR1 remote module receives an infra red signal and...

LED Light Flasher circuit

This is a very basic circuit for flashing one or more LEDS and also to alternately flash one or more LEDs. It uses a 555 timer setup as an astable multivibrator with a variable frequency. With the preset at its max. the flashing rate of the LED is about 1/2 a second. It can be increased by...

Bell circuit with two 555 timers

This simple Bell circuit uses two 555 timers. The frequency is controlled by the capacitors that must be preserved almost identical in value to each other for best results. Fine tuning is done with R1 and R2.

Long time delay

In the 556 timer, the timing is a function of the charging rate of the external capacitor. For long time delays, expensive capacitors with extremely low leakage are required. The practicality of the components involved limits the time between pulses to something in the neighborhood of 10 minutes....

Binary Counter using 555 and 4042B

In this circuit diagram, an NE555 timer is used as a pulse generator producing pulses at about one-second duration. This is governed by the timing components connected to pins 2, 6, and 7. If the 100µF capacitor connected on pins 2 and 6 were reduced to 47µF, then the counting pulses will be...