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Δικάναλος Ήχος
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Τεχνικά θέματα Ήχου - Ακουστική χώρων
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<blockquote data-quote="gfle" data-source="post: 18297" data-attributes="member: 71"><p><strong>Απάντηση: Re: Απάντηση: Υπάρχει αντιστοιχία Α τάξης και Α-Β ;</strong></p><p></p><p></p><p></p><p><a href="http://sound.westhost.com/class-a.htm" target="_blank">http://sound.westhost.com/class-a.htm</a></p><p><a href="http://sound.westhost.com/project10.htm" target="_blank">http://sound.westhost.com/project10.htm</a></p><p></p><p>Determining The Optimum Current </p><p>The ideal operating current for a Class-A amp will be about 110% of the peak speaker current. If the loudspeaker system has a nominal impedance of 8 Ohms (the design impedance for this amp), then with a +/- 22V supply the maximum (theoretical) speaker current is </p><p></p><p>I = V / R = 22 / 8 = 2.75A</p><p>In my original calculations, I actually decided on a quiescent current of 2.6A - this is really Ok, because the above calculation does not consider the losses in the output stage. In practice, it is likely that up to 3 Volts will be lost in the output circuit, based on the losses in the output devices, emitter resistors and driver transistors. </p><p>This now gives a maximum voltage of 19V peak (2.375A @ 8 Ohms). Applying the 110% fudge factor gives an operating current of 2.6125A, or 2.6 close enough. If these peaks are met in practice, this gives an output power of 22.5W into 8 Ohms. </p><p></p><p>Note that the current in the -ve supply rail remains constant, but that in the +ve supply rail will vary from the normal steady state current (same as the -ve supply). At signal extremes, the current will double (upper transistors turned on), or will drop to almost zero for negative peaks. This is common for single-ended Class-A amplifiers, although you will not see it in the text for most designs. This can complicate the design of the power supply. </p><p></p><p>Χοντρα χοντρα, η ισχυς σε ταξη Α ισουται (ειναι λιγο μικροτερη στην πραγματικοτητα) με την αντισταση φορτιου επι το τετραγωνο του ρευματος ηρεμιας .</p></blockquote><p></p>
[QUOTE="gfle, post: 18297, member: 71"] [b]Απάντηση: Re: Απάντηση: Υπάρχει αντιστοιχία Α τάξης και Α-Β ;[/b] [url]http://sound.westhost.com/class-a.htm[/url] [url]http://sound.westhost.com/project10.htm[/url] Determining The Optimum Current The ideal operating current for a Class-A amp will be about 110% of the peak speaker current. If the loudspeaker system has a nominal impedance of 8 Ohms (the design impedance for this amp), then with a +/- 22V supply the maximum (theoretical) speaker current is I = V / R = 22 / 8 = 2.75A In my original calculations, I actually decided on a quiescent current of 2.6A - this is really Ok, because the above calculation does not consider the losses in the output stage. In practice, it is likely that up to 3 Volts will be lost in the output circuit, based on the losses in the output devices, emitter resistors and driver transistors. This now gives a maximum voltage of 19V peak (2.375A @ 8 Ohms). Applying the 110% fudge factor gives an operating current of 2.6125A, or 2.6 close enough. If these peaks are met in practice, this gives an output power of 22.5W into 8 Ohms. Note that the current in the -ve supply rail remains constant, but that in the +ve supply rail will vary from the normal steady state current (same as the -ve supply). At signal extremes, the current will double (upper transistors turned on), or will drop to almost zero for negative peaks. This is common for single-ended Class-A amplifiers, although you will not see it in the text for most designs. This can complicate the design of the power supply. Χοντρα χοντρα, η ισχυς σε ταξη Α ισουται (ειναι λιγο μικροτερη στην πραγματικοτητα) με την αντισταση φορτιου επι το τετραγωνο του ρευματος ηρεμιας . [/QUOTE]
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Υπάρχει αντιστοιχία Α τάξης και Α-Β ;
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