Low Duty Cycle Long Period 555 timer controlled Piezo Buzzer

Thread Starter

RBDUFFER

Joined Sep 17, 2016
6
I am trying to develop a 555 timer to turn a Peizo buzzer on for approximately one second every thirty seconds.
The attached circuit matches these requirements close enough, except that the output is ON for 95.8 percent of the time. I need it to be OFF for 95.8 percent.
I think a simple one transistor inverter can be put on pin 3 to drive the Piezo buzzer but I don't know how to design it.

I would appreciate any hellp you could give me.

Thanks
 

Attachments

crutschow

Joined Mar 14, 2008
23,776
I think dannyf is being too pessimistic. :)
30 seconds should not be a problem for the 555 with the values you show unless you have stringent timing requirements.
 

Kjeldgaard

Joined Apr 7, 2016
381
To reverse the output pulse, and maintain the buzzer to GND, the following must be possible for the schematic from post #1:
Swap values for R1 and R2
Put a small-signal diode across R2 with the anode to pin 7
 
Top