Help on Buzzer Circuit

Hi All,

I'm not very good at designing circuits, and would like to enquire about building a small circuit. I would like to design a circuit with a buzzer that activates when a signal is transmitted from a microcontroller. This means when then microcontroller outputs a high (TTL), the buzzer activates. I would like to couple the buzzer to a 9V battery.
Please help.

Thanx

a few ways to do that .............

Hi.

Thanx for the suggestion.

The circuit posted should have a resistor in series with the LED in the opto coupler in order to limit the current. I suggest 330 Ohm.

Also, the buzzer appears to be reversed. He has shown the + side of it connected to the - side of the battery via the opto.

Len

ljcox is correct on both counts , Iposted the wrong drawing. I just got hijaak to migrate DXF to GIF and was learning that program.....sorry. Correct file: