depolo@eniac.seas.upenn.edu (Jeff DePolo) (02/13/89)
Has anyone played with the Radio Shack audio amplifier IC? I don't remember the model # or catalog #, but it's a 8-pin IC. I have a few of them that I got god knows where (some surplus stuff), and they come with the pin-outs, but no specifications. There are 2 pins labled Gain. I supposed I have to connect them via a resistor or something to adjust the amplifier gain, but I don't know what I need. I've had the amplifier working, but they seem to overdrive themselves and eventually burn out. Does anybody have any information on them? --- Jeff +----------------------------------------------+------------------------------+ | Jeff DePolo [depolo@eniac.seas.upenn.edu] | o The best things in life | | => The University of Pennsylvania <= | come in six-packs. | | Class of 1991 - Computer Science Engineering | o Life begins at 85 MPH. | +----------------------------------------------+ o It's not illegal if they | | DISCLAIMER: Someone else used my account. | don't catch you. | +----------------------------------------------+------------------------------+
frank@ut-emx.UUCP (Frank Abernathy) (02/14/89)
In article <7901@netnews.upenn.edu>, depolo@eniac.seas.upenn.edu (Jeff DePolo) writes: > > Has anyone played with the Radio Shack audio amplifier IC? I don't > remember the model # or catalog #, but it's a 8-pin IC. I have a few Delete some stuff.... > burn out. Does anybody have any information on them? It's probably the LM386, ask to look in one of their Semiconductor Ref books. It is in there. Take some scratch paper with you, or buy the book. ~$4.00.
pfales@ttrde.UUCP (Peter Fales) (02/14/89)
In article <7901@netnews.upenn.edu>, depolo@eniac.seas.upenn.edu (Jeff DePolo) writes: > > Has anyone played with the Radio Shack audio amplifier IC? I don't > remember the model # or catalog #, but it's a 8-pin IC. I have a few > of them that I got god knows where (some surplus stuff), and they come > with the pin-outs, but no specifications. There are 2 pins labled > Gain. I supposed I have to connect them via a resistor or something to > adjust the amplifier gain, but I don't know what I need. I've had > the amplifier working, but they seem to overdrive themselves and eventually > burn out. Does anybody have any information on them? This is probably the LM386 (National Semiconductor). I know RS sells the LM386 and it comes in an 8 pin package. According to my data book the simplest configuration has a gain of 20 with nothing connected to pins 1 and 8. With a 10 microfarad capacitor between the two pins (+ on pin 1) the amplifier has a gain of 200. Intermediate values can be selected by also putting a resistor (value not given) in series with the capacitor. The chip has internal 1.35K resistor between the pins. How are you driving the speaker? The chip can drive an 8 ohm speaker directly, but should have a 250 microfarad cap in series with the speaker to filter out any DC. -- Peter Fales AT&T, Room 2F-217 200 Park Plaza UUCP: ...att!ttrde!pfales Naperville, IL 60566 Domain: pfales@ttrde.att.com work: (312) 416-5357