Capacitors can be connected in series and in parallel. The resulting capacity in both cases is calculated using the formulas. Such a connection is used in cases where there are no capacitors with the required parameters, but there are others.
Necessary
- - soldering iron;
- - wires;
- - nippers;
- - calculator.
Instructions
Step 1
Any capacitors can be connected only when they are discharged and disconnected from the rest of the circuit elements. Do not short-circuit them - use a suitable load. Connect it with insulated wires without touching live parts. After discharging the capacitor, check with a voltmeter that it is really discharged, also using probes with insulated wires and handles and not touching live parts.
Step 2
Before carrying out calculations, the capacitance of the capacitors should be converted to the same units. In this case, it is irrational to use the SI system, since the unit included in it - farad - is very large. Depending on which capacitors you are connecting, you can use picofarads, nanofarads, or microfarads.
Step 3
By connecting capacitors in parallel, calculate the resulting capacitance by simply summing the capacitances of all capacitors. The operating voltage of this design will be equal to the smallest of the operating voltages of the capacitors included in it.
Step 4
When connecting capacitors in series, first find the reciprocal of the capacitance of each of them, then add these values, and then find the reciprocal of the sum. The reciprocal is the result of dividing one by a number. This looks like this: Cresult = 1 / (1 / C1 + 1 / C2 +… + 1 / Cn), where Cresult is the resulting capacitance, and C1… Cn is the capacitance of the capacitors in the series chain. The operating voltage of this design is more difficult. In theory, when capacitors of the same capacity are connected in series, it is enough to add their operating voltages, and if their capacities are different, then the voltages will be distributed across them in inverse proportion to the capacitances. In practice, parameter variations and leaks can lead to unpredictable voltage distributions. Therefore, it is most reliable to be guided by the same rule as with parallel connection: the operating voltage of the entire structure is equal to the operating voltage of that of the capacitors, which has the smallest one.
Step 5
When mixed (series-parallel) capacitors are connected, divide the design into groups of capacitors connected in series only or in parallel only. Calculate the parameters of each of the groups, and then consider it as one capacitor with the corresponding parameters. After that, look at how these groups are connected - in series or in parallel - and calculate the parameters of the entire structure using the appropriate formula. Connect polar capacitors in the same polarity, and in the same polarity include the structure in the circuit where it will work. It is not recommended to connect anti-series two polar capacitors, even of the same capacity, to obtain a non-polar one - the spread of parameters and leaks can lead to their failure. At least one polarized capacitor makes the entire structure polar.
Step 6
Sometimes electrolytic capacitors are shunted (connected in parallel) with ceramic of much smaller capacity. In this case, you do not need to count anything by the formulas, because the addition of capacity can be neglected. And they do this not to increase the capacitance, but to filter out high-frequency interference, which is not removed by electrolytic capacitors due to parasitic inductance.
