HIGH SOUND OUTPUT BEEPER CIRCUIT (7) (beeper)
I you need a real loud beeper, this circuit
delivers about 110db (12 inches away) from a 9v
battery using a single inexpensive C-MOS IC. An
off-the-shelf piezoelectric beeping device is driven
at resonance to insure maximum efficiency. By
changing the control IC to a 74AC14, the same
circuit can operate from 3v and 1.5v batteries.
Published in Electronic Design, Aug 5, 1993 |
POWER REMINDER BEEPER: (20) (beeper2)
This circuit produces a short beep once each minute.
It is powered directly off the 120vac power line to
remind you that a device connected to the circuit is
turned on. It is simple enough to be packaged inside
a small plastic box. It might be ideal for
computers, printers or some test equipment that
shouldn't be left on all night. |
BASEMENT DOORBELL BEEPER (39) (doorbell)
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. |
MACHINE POWER LOSS BEEPER: (40) (powerlos)
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. |
VERY LOUD BEEPER CIRCUIT (51) (beeper3)
This circuit is similar to circuit number 7, but
generates a continuous tone instead of a pulsing
one. The circuit delivers about 110db (12 inches
away) from a 9v battery using a single inexpensive
C-MOS IC. An off-the-shelf piezoelectric beeping
device is driven at resonance to insure maximum
efficiency. |
ANOTHER VERY LOUD PIEZO ALARM BEEPER (67)
(beeper4)
This is yet another beeper circuit that really
draws attention. It sweeps the drive frequency
slightly to produce a very annoying sound. It uses a
transformer to increase the drive voltage across the
piezoelectric device to more than 200 volts peak to
peak. It cranks out an ear splitting 120db when
measured at 12 inches. |