Beeper Buzzer

Put the car in reverse and the circuit provides a loud, audible beep at the rate of about one per second (1Hz). Half of U1, a 556 dual oscillator/timer, is used as a slow-pulse oscillator with a rate of about 1Hz. Components R2, R1, and C1 form the long time constant. You can calculate on time by t~.7 (R1 + R2) C1 or 1.15 seconds. The off time is shorter than the on time, at . 77 second. Enabling pin 4 (reset) is held high to keep the oscillator freerunning when voltage is.....

Views: 33 | Votes: 81 | Comments: 0 | Rating: 0 | Rank: 5 | Added: Feb 22, 2013 |

Using a PA41 from Apex Microtechnology, this monolithic amplifier is capable of 350-V operation ..

Views: 18 | Votes: 22 | Comments: 0 | Rating: 9 | Rank: 5 | Added: Feb 6, 2013 |

This circuit does not require an output transformer or an output coupling capacitor; the annunciator can easily be turned on or off by a control input voltage driving a 10Mohm input resistor, R3. For a smaller acoustic output, replace output transistor Ql, with a 100ohm resistor, ..

Views: 18 | Votes: 96 | Comments: 0 | Rating: 8 | Rank: 5 | Added: Dec 21, 2012 |

A CMOS-gate and transistor buffer can be used as an effective driver..

Views: 17 | Votes: 38 | Comments: 0 | Rating: 3 | Rank: 5 | Added: Dec 19, 2012 |

This circuit uses a CA5422 dual BiMOS microprocessor op amp. The bootstrap amplifiers minimize bias currents while maintaining electrostatic discharge protection. ..

Views: 9 | Votes: 18 | Comments: 0 | Rating: 3 | Rank: 5 | Added: Dec 12, 2012 |

When the vehicle"s backup lights kick on, or when the manual switch (SI) is closed, a small current is fed to the base of Ql...

Views: 17 | Votes: 68 | Comments: 0 | Rating: 5 | Rank: 5 | Added: Dec 1, 2012 |

A self-interrupting device connected to a voltage source functions as a switch that repeatedly open..

Views: 12 | Votes: 38 | Comments: 0 | Rating: 8 | Rank: 5 | Added: Nov 25, 2012 |

The PA41 from Apex Microtechnology is used here to drive a piezoelectric micropositioner...

Views: 8 | Votes: 72 | Comments: 0 | Rating: 0 | Rank: 5 | Added: Nov 24, 2012 |

This circuit will generate an ear-splitting 110 dB from 9 V. The setup uses a single 74C14 (CD40106B) CMOS hex inverting Schmitt-trigger IC, wliich must be used with a piezoelectric device with a feedback terminal. The feedback terminal is attached to a central region on the piezoelectric wafer. When the beeper is driven at resonance, the feedback signal peaks. One inverter of the 74C14 is wired as an astable oscillator, The frequency is chosen to be 5 times lower than.....

Views: 21 | Votes: 79 | Comments: 0 | Rating: 1 | Rank: 5 | Added: Nov 11, 2012 |

This circuit uses a CA5470 quad microprocessor BiMOS-E op amp. Amplifiers Al and A2 are employed as a cross-coupled differential input and differential output preamp stage and A3 provides input guard-banding. ..

Views: 7 | Votes: 99 | Comments: 0 | Rating: 9 | Rank: 5 | Added: Jul 29, 2012 |

One small spot of rain on the sense pad of this bleeper will start this audio warning. It can also be operated by rising water. The circuit has two transistors, with feedback via capacitor Cl, but Trl cannot operate as long as the moisture sense pad is dry. ..

Views: 2319 | Votes: 55 | Comments: 0 | Rating: 1 | Rank: 4 | Added: Jun 24, 2012 |

This circuit uses a 4049 IC to drive a 2N2222 switching transistor...

Views: 9 | Votes: 49 | Comments: 0 | Rating: 1 | Rank: 5 | Added: Jun 14, 2012 |

Resistor R1, capacitor C1, and two converters form a square wave generator, which produces the basic tone. The generator is sui followed by an inverter which serves as both a buffer and a driver for the President. The resistor R2, which has a minimum value of 100 ohms, limits the power and volume controls. The diode D1, capacitor C2, resistors R3 and R4, and two in converters to create the pulse generator which determines the power-up and decay times of the ring. ..

Views: 2822 | Votes: 50 | Comments: 0 | Rating: 5 | Rank: 4 | Added: Apr 13, 2012 |

The signal from COR triggers U1 which produces a beep-gate pulse that enables the analog gate..

Views: 3401 | Votes: 100 | Comments: 0 | Rating: 1 | Rank: 5 | Added: Apr 5, 2012 |

For some medical equipment it is important for an operator when power is lost to the machine. The beeper is powered from a 9v battery and requires the machine to have a power switch with a third set of contacts...

Beeps when hears your whistle A gadget suitable for key-holders, games etc. These devices contained a special purpose IC and therefore were not suited to home construction. The present circuit is designed around a general purpose hex-inverter CMos IC and, using miniature components and button clock-type batteries can be enclosed in a matchbox. It is primarily a gadget, but everyone will be able to find suitable applications...

This novel buzzer circuit uses a relay in series with a small audio transformer and speaker. When the switch is pressed, the relay will operate via the transformer primary and closed relay contact. As soon as the relay operates the normally closed contact will open, removing power from the relay, the contacts close and the sequence repeats,..

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...

This novel buzzer circuit uses a relay in series with a small audio transformer and speaker. When the switch is pressed, the relay will operate via the transformer primary and closed relay contact. As soon as the relay operates the normally closed contact will open, removing power from the relay, the contacts close and the sequence repeats, all very quickly.....

This circuit is based around the 555 timer circuit, used as an astable (free running) oscillator. The frequency (pitch) of the tone is set by the resistors and capacitors in the left side of the circuit. The first one is a potentiometer (variable resistor), this is our pitch control, which is basically all the external components you need. The capacitor to the far left is to reduce as much noise or undesired operation of the potentiometer, getting a smooth pitch change.....