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回复：【Howland电流泵电路】 | 论坛

2019-11-19 仁杰

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回复：【Howland电流泵电路】 | 论坛

2019-11-19 仁杰

<span style="background-color:#FFFFFF;"><span><span><span><span><span><span style="font-size:16px;font-weight:700;">所需<a href="http://www.hqchip.com/?u=999" target="_blank" class="relatedlink">元器件</a></span></span></span></span></span></span></span><br /> <br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>运算放大器-LM741</span></span></span></span></span></span><br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>电阻-3.9kΩx2+1kΩx3</span></span></span></span></span></span><br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>9V<a href="http://bbs.elecfans.com/zhuti_power_1.html" target="_blank" class="relatedlink">电源</a></span></span></span></span></span></span><br /> <br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span><span style="font-size:16px;font-weight:700;">运算放大器LM741</span></span></span></span></span></span></span><br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>LM741运算放大器是一个直流<a href="http://www.elecfans.com/tags/%E8%80%A6%E5%90%88/" target="_blank" class="relatedlink">耦</a>合的高增益放大器，一共有8个引脚。这里的运算放大器会作为比较器来对比两个型号，同相信号和反向信号。引脚2为反向输入引脚，引脚3为同相输入引脚。输出引脚为引脚6。该运放的主要作用是在多种电路中进行数学运算。</span></span></span></span></span></span><br /> <br /> <span style="background-color:#FFFFFF;"><span><span><span><span>当同相引脚（+）的电压高于反向引脚（-）时，比较器输出为高，反之则为低。</span></span></span></span></span>

回复：【Howland电流泵电路】 | 论坛

2019-11-19 仁杰

<span style="background-color:#FFFFFF;color:#666666;font-family:Tahoma,&quot;Microsoft Yahei&quot;,&quot;Simsun&quot;;font-size:13px;font-style:normal;font-weight:400;text-decoration:none;">感谢分享 </span><br />

回复：【杭州方向招聘：北京大学信息技术高等研究院招嵌入式等工程师，提...】 | 论坛

2019-11-19 仁杰

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回复：【Howland电流泵电路】 | 论坛

2019-11-19 仁杰

<span style="background-color:#FFFFFF;"><span><span><span><span><span>io = i1 +i2</span></span></span></span></span></span><br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>io = (V1 – VL / R3) + (VA – VL / R4) …(等式1)</span></span></span></span></span></span><br /> <br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>R1、R2和运放组成了一个同相<a href="http://www.elecfans.com/tags/%E6%94%BE%E5%A4%A7%E5%99%A8/" target="_blank" class="relatedlink">放大</a>器，输入电压为负载电压VL。因此可得</span></span></span></span></span></span><br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>VA = (1 + R2 / R1) VL … (等式2)</span></span></span></span></span></span><br /> <br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>将等式2中的VA代入等式1可得</span></span></span></span></span></span><br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>io = (V1 – VL / R3) + ((1 + R2 / R1) VL – VL / R4)</span></span></span></span></span></span><br /> <br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>现在通过将io=AV1-VL/Ro放到等式里求解，其中A=1/R1</span></span></span></span></span></span><br /> <br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>因此等效电阻Ro=R4/((R4/R3)-(R2/R1))</span></span></span></span></span></span><br /> <br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>因此为了保证输出电流的恒定且与负载阻值无关，我们需要实现一个平衡的电阻桥，即</span></span></span></span></span></span><br /> <span style="background-color:#FFFFFF;"><span><span><span><span><span>R4/R3=R2/R1</span></span></span></span></span></span>

回复：【Howland电流泵电路】 | 论坛

2019-11-19 仁杰

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回复：【Howland电流泵电路】 | 论坛

2019-11-19 仁杰

【Howland电流泵电路】 | 论坛

2019-11-19 仁杰

<span style="background-color:#FAFAFA;color:#666666;font-family:Tahoma,&quot;Microsoft Yahei&quot;,&quot;Simsun&quot;;font-size:12px;font-style:normal;font-weight:400;line-height:22px;text-decoration:none;">感谢分享，欢迎关注我，资料持续更新中。有需要机械臂，电源，硬件电路设计，软件编程，开发板等各种定制的可以私聊我哦，相互学习，共同进步</span>

回复：【【资料包】2.4G资料包】 | 论坛

2019-11-19 仁杰

<span style="background-color:#FAFAFA;color:#666666;font-family:Tahoma,&quot;Microsoft Yahei&quot;,&quot;Simsun&quot;;font-size:12px;font-style:normal;font-weight:400;line-height:22px;text-decoration:none;">感谢分享，欢迎关注我，资料持续更新中。有需要机械臂，电源，硬件电路设计，软件编程，开发板等各种定制的可以私聊我哦，相互学习，共同进步</span>

回复：【创龙TI KeyStone C66x的温度传感器、B2B连接...】 | 论坛

2019-11-19 仁杰