Printer version
Highpass Filter
To determine the crossover frequency a certain amount of capacitance will give you, use the formula:
0.159/(C x Rh) = F
Explanation of Terms
C
- is the capacitance value (in Farads) - to convert to Farads divide the value shown on the side of the cap in uF by one million.
Rh
- is the impedance of the load (speaker) you will be using.
F
- is the crossover frequency you will get.
by frequency
Crossover Frequency (Hertz)
Capacitance uF (microFarad)
8 Ohms
4 Ohms
2 Ohms
80
248.44
496.88
993.75
100
198.75
397.50
795.00
120
165.63
331.25
662.50
150
132.50
265.00
530.00
200
99.38
198.75
397.50
280
70.98
141.96
283.93
400
49.69
99.38
198.75
600
33.13
66.25
132.50
800
24.84
49.69
99.38
1000
19.88
39.75
79.50
1200
16.56
33.13
66.25
2000
9.94
19.88
39.75
4000
4.97
9.94
19.88
5000
3.98
7.95
15.90
6000
3.31
6.63
13.25
8000
2.48
4.97
9.94
10000
1.99
3.98
7.95
12000
1.66
3.31
6.63
by capacitor
Capacitance uF (microFarad)
Crossover Frequency (Hertz) approximate
8 Ohms
4 Ohms
2 Ohms
2.2
9034
18068
36136
3.3
6023
12045
24091
4.7
4229
8457
16915
6.8
2923
5846
11691
10.0
1988
3975
7950
22
903
1807
3614
50
398
795
1590
100
199
398
795
200
99
199
398
Calculate for any Value
To use this calculator, enter the amount of capacitance you have available in the first box. Then enter the impedance of the speaker you will be using with this filter in the box below that. Finally, click the "Calculate It" button to see the frequency this filter will be -3 dB.
Capacitor =
uF
Rh =
Ohms
Answer =
Hertz
Capacitors in Series/Parallel
To use this calculator, enter the amount of capacitance in the first two boxes, they can be different values - this is how you obtain the odd values in the charts above. Then pick a series or a parallel connection. Now, click the "Capacitance" button to see the resulting value.
Capacitor 1 =
uF
Capacitor 2 =
uF
Connection
Parallel
Series
Answer =
uF
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