Quick question about a LogicWorks symbol

[zeo_max]

Hello everyone, I'm new here.

I would like to know how to use the "SPEAKER" symbol in LogicWorks 5. I'm not sure what to connect to each pin to make it work, and I would like to know wether it makes a sound or not.

This is the symbol I'm talking about :

**broken link removed**

Thanks for your help

 

[Papabravo]

You can think of the speaker as the coil of an electromagnet. Connecting any kind of a DC source across the terminals won't do much in the sound department. If the source has enough current it might produce some magic smoke as it vaporizes the wire in the coil.

Connect an AC source and now the speaker cone will vibrate in sync with the AC signal and produce -- SOUND. Does this mean you can plug the terminals into a wall socket? NO too much current -- magic smoke, burnt fingers, yadda yadda yadda.

Google for "Audio Amplifier Circuits" to find examples of circuits for driving speakers.

 

[Hero999]

Connect it to the output an astable 555 timer running at an audiable frequency via a 4.7:mu:F capacitor.

 

[zeo_max]

Connect it to the output an astable 555 timer running at an audiable frequency via a 4.7:mu:F capacitor.

I can't find the 555 timer in LogicWorks. Maybe I'm already using it but don't know exactly what it's called. Do you know what name does LogicWorks use for the 555 timer ?

 

[Hero999]

I don't use logic works.

Have you searched the help file?

 

[zeo_max]

I don't use logic works.

Have you searched the help file?

Yep. Not much help. I'm guessing that their 555 timer is just the clock (pulse train) that is used to drive flip-flops and such. But I don't know how I would attach that to drive the speaker.

Here is the symbol for the clock :

**broken link removed**

Any ideas ?

BTW, thanks for all the help you guys have given me so far.

 

[audioguru]

Is your stupid sim software smart enough to know that an 8 ohm speaker connected to the output of a 555 through a puny 4.7uF capacitor will overload the 555 if the frequency is high?

Speakers are driven from power amplifiers.

 

[Hero999]

That's true, I should've said, 1kHz.

 

[audioguru]

A little 4.7uF capacitor has a reactance of 34 ohms at 1kHz.
A pretty big 8 ohm woofer has an inductance that increases it impedance to about 20 ohms at 1kHz. So if the 555 has a supply voltage of about 7V or less then the output won't deliver more than its max rating of 200mA.

 

[Hero999]

A pretty big 8 ohm woofer has an inductance that increases it impedance to about 20 ohms at 1kHz.

Don't be silly you'd have to be pretty stupid to connect a big woofer to a 555 timer.

Besides, the inductive impedance will subtract from the capacitive impedance of the capacitor. If the woofer has total impedance of 20hm: @ 1kHz, that's 18.33hm: of inductive impedance giving of 15.67hm: of capacitive impedance and a total impedance of 17.59hm:.

Obviously I was talking about a small speaker with negligible inductance, <500:mu:H, giving an impedance of 3.1hm:.

Don't forget the saturation voltage of the 555 is about 2V.

 

[audioguru]

I was saying that a 555 shouldn't be used to drive a speaker.

 

[Hero999]

There is nothing wrong with using a 555 to power a speaker low power levels.