Electronic – the purpose of the 250uF capacitor in the LM386 circuit

high pass filterlm386

The basic amplification schematics shown in the LM386 datasheet shows a 250 uF capacitor in series with the output. I don't have any 250 uF, but I do have plenty of 470uF. If I understand correctly, is this capacitor used as a high pass filter, so should I be able to use a 470 uF instead of a 250 uF?

Also, is the resistor (10 ohm) and capacitor (0.05 uF) going to ground a low pass filter?

Best Answer

Yes, 470uF will work fine, it will just extend the bass response somewhat. It's a coupling capacitor (or a blocking capacitor, to block DC, if you prefer).

The 10R + 50nF is a "Zobel Network", intended to cancel out the reactive portion of the speaker impedance.