| 首页 | 汽车电路图 | 手机电路图 | mp3电路图 | 功放电路图 | 主板电路图 | 显示器电路图 | 电磁炉电路图 | 开关电源电路图 | 电视机电路图 |
| 收音机电路图 | 电源电路图 | 充电器电路图 | 耳机电路图 | 滤波电路 | 遥控器电路图 | usb电路 | 放大电路 | 防盗报警器 | 振荡电路 |
| 控制电路 | 脉冲电路 | 保护电路 | 电话机 | LED电路 | 电饭堡电路 | 热水器电路 | 传感器电路 | 小家电电路 | 温度计 | 电动自行车 |
|
前一个电路图:Hi-Fi 前置放大器 |
ECM 麦克前置放大器
Both transistors are low noise types. In the original circuit, I used BC650C which is an ultra low noise device. These transistors are now hard to find but BC109C are a good replacement. The circuit is very device tolerant and will set its quiescent point at roughly half the supply voltage at the emitter of the last transistor.
The electret condenser microphone (ECM) contains a very sensitive microphone element and an internal FET preamp, a power supply in the range 2 to 10 volts DC is therefore necessary. Suitable ECM's may be obtained from Maplin Electronics. The 1k resistor limits the current to the mic. The output impedance is very low and well suited to driving cables over distances up to 50 meters. Screened cable therefore is not necessary.
相关电路图:
 电缆测试电路 | 基本RC桥式振荡电路 | |
|
|
||
| 具有稳幅环节的RC桥式振荡电路 | 2W 音频放大器 | |
|
|
||
| 4管发射机原理图 | 过零脉冲电路(实验验证过) | |
|
|
||
| 5.1ch 功放电路 | 5.1c功放系统 | |
|
|
||
| 7107做的电压表（双表） | IC卡读写器原理图 | |
|
|
||
| USB多媒体2.5W+2.5W | 光控、单按键开关壁座电路 | |
|
|
||
| 几种VI转换和恒流源电路图的比较 | 开关电源式高压恒流源电路图 | |
|
|
||
| 门铃电路 | 新构思电子保险丝 | |
|
|
||
|
电子技术下载网 | 网站地图 | 联系我们 | 免责声明 | 招聘信息 | 友情链接 Copyright © 2005 - 2007 电子电路网 - 单片机设计网下属站点 |