Research and Application of RC Frequency Selection Network
The RC frequency selection circuit has a very important position in the circuit, and it is a circuit that has been studied early. It has a wide range of applications in circuits, and RC frequency selection circuits are used in many appliances in daily life, so it has very important significance for its research. In this article, I will design and study it and discuss its practical application and how to improve it.
Keywords: RC frequency selection, oscillator circuit,
text:
Experimental tool: circuit simulation software MulTIsim7.0.
Experimental principle:
Circuit network function Kv = U2 / U1 = ((R2 * (1 / JWC2)) / (R2 + 1 / JWC2)) / ((R2 * (1 / JWC2)) / (R2 + 1 / JWC2) + R1 + 1 / JWC1)
= 1 / (1+ (R1 + (1 / JWC1)) (1 / R2 + JWC2))
= 1 / (1 + R1 / R2 + C2 / C1 + R1C2JW + 1 / R2C1JW)
To maximize the value of Kv, the imaginary part in the above formula should be zero. then
R1C2JW + 1 / R2C1JW = 0,
Solved: W = 1 / (C1C2R1R2)
So: f0 = 1 / 2Î (C1C2R1R2)
And R1 = 80, R2 = 60, C1 = 2, C2 = 3, bring it into the formula and find f0 = 938
The design route and parameters of the experiment are as follows:
Adjust the frequency of the voltage source of the circuit to record the indication of each voltmeter, draw the corresponding table, and draw the amplitude and phase frequency curves of RC:
The data table is as follows:
f0 (HZ) U2 (V) U1 (V) U1 / U2 Us (v)
700 220 56.065 0.2548 220
800 220 56.998 0.2591 220
820 220 57.111 0.2596 220
840 220 57.203 0.2600 220
860 220 57.275 0.2603 220
880 220 57.328 0.2606 220
900 220 57.365 0.2607 220
920 220 57.386 0.2608 220
940 220 57.391 0.2609 220
960 220 57.382 0.2608 220
980 220 57.360 0.2607 220
1000 220 57.326 0.2606 220
1050 220 57.191 0.2600 220
1150 220 56.741 0.2579 220
1250
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