CBB's secret to eliminate electrolytic capacitors

When it comes to CBB capacitors, everyone may be unfamiliar, but if you mention electrolytic capacitors, most people will not feel strange. Electrolytic capacitors are widely used and once used as one of the mainstream capacitors, but they are gradually being replaced by CBB capacitors. So why do CBB capacitors gradually start to replace electrolytic capacitors?

What is the meaning of these two capacitors?

1. CBB capacitor:

Non-polarity, high insulation resistance, excellent frequency characteristics (wide frequency response), and low dielectric loss. Based on the above advantages, thin-film capacitors are used in large numbers in analog circuits. Especially in the signal cross-connected part, a capacitor with good frequency characteristics and very low dielectric loss must be used to ensure that no distortion occurs when the signal is transmitted. High dielectric constant, small size, large capacity, good stability, suitable for bypass capacitors. Polystyrene film capacitors, small dielectric loss, high insulation resistance, but large temperature coefficient, can be used for high-frequency circuits.

2. Electrolytic capacitor features:

A polar electrolytic capacitor usually functions as a power supply filter, decoupling, signal coupling, time constant setting, and DC blocking in a power supply circuit or an intermediate frequency circuit or a low frequency circuit. Generally can not be used for AC power circuit, when used as a filter capacitor in the DC power circuit, the anode (positive) should be connected to the positive terminal of the power supply voltage, and the cathode (negative) should be connected to the negative terminal of the power supply voltage. , otherwise it will damage the capacitor. Non-polar electrolytic capacitors are commonly used in speaker divider circuits, TV S correction circuits, and start-up circuits for single-phase motors.

Electrolytic capacitors are widely used in home appliances and various electronic products, and have a large capacity range, generally 1 to 1000 μF, and a rated operating voltage range of 6.3 to 450V. The disadvantage is that the dielectric loss and capacity error are large (the maximum allowable deviation is +100%, -20%), and the high temperature resistance is poor, and the storage time is long and it is easy to fail.

Back to the beginning of the question, why is the electrolytic capacitor eventually replaced by the CBB capacitor? This is because the type of filtering has changed, the DC filter uses a polar electrolytic capacitor, and the AC wave is filtered to use a non-polar CBB capacitor when filtering is needed. When AC waves are used, CBB capacitors are used instead of motor capacitors. And when the circuit is a high-frequency circuit, it is necessary to use CBB capacitors.

At present, there are more and more applications of AC waves, and more and more devices use AC waves, so people will have the illusion that CBB capacitors gradually replace electrolytic capacitors. In fact, in the application of DC is still inseparable from the electrolytic capacitor. I hope everyone will have a clear understanding of the difference between electrolytic capacitors and CBB capacitors after reading this article.