Categories
Audio
Amplifiers, Audio Filters, Beeper & Buzzer, Equalizers, Intercom Circuits, Microphone Circuits, Mixers, Musical Circuits, Preamplifiers, Stereo Circuits, Tone-Balance, Ultrasonic Circuits, Vacuum Tubes, ...
|
Automations
|
Automotive
|
Computer
|
Converters
|
Digital
|
Inside Circuits |
Light-Laser-LED
|
Meter/Counter
|
Microcontrollers
|
Oscillators
Astable, Audio, Colpitts, Crystal, Hartley, Monostable Circuits, Pierce, RF, Sine wave, Square wave, Volt controlled, Wein Bridge, ...
|
Other Circuits
Buffer Circuits, Demodulators, Doorbell Circuits, Game Circuits, H-Bridge Circuits, Keypad Circuits, Model Circuits, Mosfet Circuits, Radar Circuits, Sequencer, Switch Circuits, Triac Circuits, ...
|
Power Supplies
|
RF
AM Circuits, Amplifiers, Antennas, FM Circuits, FM Transmitters, GPS Circuits, PLL Circuits, Receivers, Transceiver Circuits, Transmitters, UHF Circuits, VHF Circuits, ...
|
Security
|
Sensors/Detectors
Air-Gas, Hall Effect, Human, Light, Liquid, Magnetic circuits, Medical, Metal Detector circuits, Optical, RF & Radiation, Various Circuits, Voltage, ...
|
Software
|
Telephone
|
Video
|
|
Doorbell Circuits
|
This circuit is a modified "Hartley Oscillator" with a couple extra parts. T1, the LT700 (or equivalent, is a small center tapped (ct) audio transformer with an impedance of 1000 ohms at 1000 hertz. The secondary of this transformer has an impedance of 8 ohms. Usually noted as 1K:8 ct.
http://www.uoguelph.ca/~antoon/circ/canary.html
 PageRank: 0/10
(Clicks: 676;
Listing added: May 27, 2007)
|
|
This circuit is a modified hartley oscillator with a couple of extra components included. The transformer is a small audio transformer, type LT700. The primary is center tapped with an impedance of 1Kohms at 1KHz . The secondary has an impedance of 8 ohms. The inclusion of R1 and C1 give this oscillator its characteristic "chirp". As the 100u capacitor charges via the 4.7K resistor, R1 the bias for the transistor is cut off.
http://www.zen22142.zen.co.uk/Circuits/Music/canary.htm
 PageRank: Not available
(Clicks: 490;
Listing added: Mar 20, 2008)
|
|
This simple and cost-effective door
bell circuit is based on IC 8021-2
from Formox Semiconductors
(Website address: fortech@mantramail.
com). It is an 8-pin DIP IC whose only
four pins, as shown in the circuit, have
been used.
http://www.electronicsforu.com/efylinux/circuit/feb2003/mar02_ding-dong.pdf
 PageRank: 0/10
(Clicks: 1980;
Listing added: May 27, 2007)
|
|
The circuit in Figure 1 prevents damage to the chime and improves the chime's effectiveness by repeating the chime strike for as long as the pushbutton remains depressed. The circuit controls both front and rear chimes.
http://www.edn.com/article/CA45864.html
 PageRank: 0/10
(Clicks: 390;
Listing added: May 27, 2007)
|
|
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.
http://www.freeinfosociety.com/electronics/schemview.php?id=347
 PageRank: 0/10
(Clicks: 1653;
Listing added: May 27, 2007)
|
|
This circuit uses a synthesized sound chip from Holtek, the HT-2811. This reproduces the sound of a "ding-dong" chiming doorbell. Additionally, the circuit includes a CMOS 4026 counter display driver IC to count your visitors. The count may be expanded for up to 99 visits by cascading two CMOS 4026 IC's and using an additional 7 segment display. This is achieved by wiring pin 5 ( the 10's output ) of the first CMOS4026 to pin 1 (the clock input) of the second IC.
http://www.zen22142.zen.co.uk/Circuits/Switching/dbcounter.htm
 PageRank: 0/10
(Clicks: 924;
Listing added: May 27, 2007)
|
|
If you can't hear your doorbell when you are in your basement try this circuit. This circuit takes advantage of the 24vac power source located near the furnace. Using a simple current transformer technique, the circuit sounds a beeper whenever the main door chime is activated.
http://discovercircuits.com/DJ-Circuits/doorbel.htm
 PageRank: 0/10
(Clicks: 433;
Listing added: May 27, 2007)
|
|
This schematic will activate a beeper in the basement, whenever the front doorbell is pressed.
http://discovercircuits.com/DJ-Circuits/doorbell2.htm
 PageRank: 0/10
(Clicks: 1281;
Listing added: May 27, 2007)
|
|
This circuit provides a delayed visual indication when a door bell switch is pressed. In addition, a DPDT switch can be moved from within the house which will light a lamp in the door bell switch. The lamp can illuminate the words "Please Wait" for anyone with walking difficulties.
http://www.zen22142.zen.co.uk/Circuits/Misc/deafdoorbell.htm
 PageRank: Not available
(Clicks: 693;
Listing added: Mar 20, 2008)
|
|
The loudspeaker is a 8 Ohm type and must be larger than 200milli-Watt. I used a 2Watt type, but anything over 0.2W will do. It really sounds like a bird and when you release the doorbell button the sound slowly fades away. I have used this circuit in my house for over 20 years and even build the "Birdie" for others. Although an old circuit, the experimentation and the final results still give a punch. Remember to Have fun!
http://www.uoguelph.ca/~antoon/circ/birdie.htm
 PageRank: 0/10
(Clicks: 1886;
Listing added: May 27, 2007)
|
|
|