What are the precautions for the use of aluminum electrolytic capacitors (1)?

Precautions for the use of aluminum electrolytic capacitors

1 Precautions in circuit design

(1) After confirming the operating environment and installation environment, design the capacitor within the range of the rated performance of the capacitor specified in the product catalog of the capacitor or the application for approval of the specification (hereinafter referred to as the "Delivery Approval").

(2) The use temperature and use ripple current should not exceed the scope specified in the product catalog or delivery approval.

①Do not use it at a temperature that exceeds the upper limit temperature of the classification (maximum operating temperature).

②Do not connect through current (current exceeding the rated ripple current).

(3) When designing the circuit, please select a capacitor that matches the life of the machine.

(4) The capacitor is a polar capacitor. Check to see if reverse voltage or AC voltage is connected. Use bipolar capacitors in polarity reversal circuits. However, bipolar capacitors cannot be used in AC circuits either.

(5) In circuits that repeatedly perform rapid charge and discharge, select capacitors that match the conditions of use. As a circuit that repeatedly performs rapid charging and discharging, such as electric welding machines, camera flashes, etc. In addition, the control circuit of a rotating machine such as a servo motor, which fluctuates greatly in the circuit voltage, also repeatedly performs rapid charging and discharging. Please consult us about capacitors used in repetitive rapid charge/discharge circuits.

(6) Make sure that no excess voltage (voltage exceeding the rated voltage) passes through the capacitor.

① It should be noted that the peak value of the ripple voltage (AC part) superimposed on the DC voltage cannot exceed the rated voltage.

②When connecting two or more capacitors in series, control the voltage across each capacitor to be less than or equal to the rated voltage. Also, at this time, a voltage dividing resistor considering leakage current is added in parallel with each capacitor.

(7) Capacitors should be completely isolated from the circuit between the following.

(The aluminum shell of the capacitor and the cathode terminal are connected together by the natural oxide film inside the box and the unstable resistance part of the electrolyte)

①Between the aluminum shell and the cathode terminal (except the reverse lead terminal) and the anode terminal and the circuit board.

②Between the substrate self-supporting blank terminal and other anode terminals and cathode terminals and the circuit board.

③ Between the two terminals of the bipolar capacitor and the aluminum shell.

(8) The packaging sleeve of the capacitor is non-insulated to ensure the shape. Do not use where insulation is required. Consult us when you need an outer jacket with insulation.

(9) Capacitors may sometimes malfunction if used in the following environments.

①Ambient environment (weather resistance) conditions

(a) The environment of direct water splash, high temperature and high humidity environment and dew condensation environment (b) The environment of direct splash of oil and the environment full of oil mist

(c) The environment where salt water is directly splashed and the environment full of salt

(d) Environments filled with toxic gases (hydrogen sulfide, sulfurous acid, chlorine, bromine, methyl bromide, ammonia, etc.) (e) Environments exposed to direct sunlight, ozone, ultraviolet rays and radiation

(f) Environments with splashes of acidic and alkaline solvents

② Harsh environments where vibration or shock conditions exceed the range specified in the delivery approval

(10) When mounting a capacitor on a printed circuit board, please design after confirming the following in advance.

① Align the hole spacing of the printed circuit board with the terminal spacing of the capacitor.

②Do not place wiring and circuit board close to the pressure valve part of the capacitor during design.

③As long as there is no stipulation in the delivery acknowledgement, the pressure valve part of the capacitor should be left with a gap.

①When the pressure valve of the capacitor is installed on the side of the printed circuit board, please align the position of the pressure valve and open the exhaust hole when the pressure valve is working.

②Please face the sealing part of the screw terminal type upward. Also, when laying it horizontally, keep the anode terminal facing up.

(11) If there is a stencil on the underside of the capacitor sealing part, once the electrolyte leaks, it may cause a short circuit and cause leakage tracking or migration. Therefore, do not perform circuit stencil wiring under the capacitor sealing part.

(12) Do not place heat generating parts around the capacitor and on the back of the printed circuit board (under the capacitor).

(13) The land pattern of the printed circuit board for chip capacitors should be designed with reference to the recommended pattern in the product catalog or delivery approval letter.

(14) The electrical characteristics of capacitors vary with temperature and frequency fluctuations. Please design the circuit after confirming the amount of change.

(15) When mounting capacitors on a double-sided printed circuit board, design the circuit so that there are no extra printed circuit board holes under the capacitor and no through holes for front and back connections.

(16) The tightening torque of the screw terminals and the screws used to install the capacitor should not exceed the range specified in the delivery approval.

(17) When more than two capacitors are connected in parallel, the current balance needs to be fully considered.

(18) When connecting more than two capacitors in series, consider the voltage balance and insert a voltage divider resistor in parallel with the capacitor.