你好,欢迎访问达普芯片交易网!|  电话:010-82614113

门禁电话通话电路

发布时间:2008-12-23 00:00:00阅读:801

In this doorphone circuit,an 8 ohm speaker is used both as a microphone and also an output device. The BC109C stage amplifies in common base mode, giving good voltage gain , whilst providing a low impedance input to match the speaker. Self DC bias is used allowing for variations in transistor current gain. An LM386 is used in non-inverting mode as a power amplifier to boost voltage gain and drive the 8 ohm speaker. The 10k potentiometer acts as the volume control, and overall gain may be adjusted using the 5k preset. The double pole double throw switch, reverses the loudspeaker positions, so that one is used to talk and the other to listen. Manually operating the switch (from inside the house) allows two way communication.

ImgLoad(document.getElementById("BodyLabel"));



在线人工客服

点击这里给我发消息

点击这里给我发消息

点击这里给我发消息

010-82614113

客服在线时间周一至周五
9:00-17:30