CAPACITOR HACKS

Here are some interesting capacitor hacks that you would like to know ...

1. Why electrolytic capacitors have polarities ?

> Electrolytic capacitor has polarity markings, since the dielectric is formed by chemical reaction between electrolytes and anode plate, which holds some potential inside them. There dielectric is oxide layer which is formed by passing current in one direction from anode to electrolyte.

2. What will happen if we reversed polarity of capacitor ?

>?If the polarity is reversed while connecting, the dielectric in the form of oxide layer is damaged. A heavy current flows, large amount of heat is generated and capacitor gets damaged. An explosion can result if it not provided with safety against explosion. But this happens with only polarized capacitor non polarized capacitor doesn't get damage.

3. Why do electrolytic capacitors have positive and negative terminals whereas the polarity of charge changes according to the charging and discharging of the capacitor ?

> An uncharged capacitor does contain a positive and negative terminal when a DC voltage is connected across the capacitor then electrons are coming out from plate nearer to the positive terminal of the battery and lacking of electrons in that plate makes it positive and plate nearer to negative terminal of battery will gain electrons and will be negative in this way capacitor gets charged.

In case of electrolyte capacitor we observe positive and negative terminals because capacitor actually holds some potential energy in it by transferring the charge from one plate to another. Incoming and outgoing charges are same hence its potential energy maintains positive terminal positive and negative negative.

4. How to test capacitors using multimeter ?

> i. Remove capacitor from circuit board and make sure it is completely discharged. It is important to make sure whether it is completely discharge or not because high value capacitor may result in shock.

??ii. Set multimeter to measure resistance, if there are multiple ranges of resistance measurement select high range.

??iii. Connect probes of multimeter to capacitor and observe resistance repeat same for few times.

??iv. When you will measure resistance in non polarized capacitor it will first start to increase and then it will go to infinity and if capacitor is polarized it has some fixed voltage in it so it will show some resistance this resistance will be same all the time.

5. What is use of capacitor and how to select which type of capacitor should be used for that application ?

>?One application requires one type of capacitor and another application requires another type of capacitor. I.e. Same type of capacitor is not used for all applications. So choosing right capacitor for application is important. Below are the parameters that should be considered ...

i. Capacitance of capacitor?????ii. Working voltage?????iii. Polarization?????iv. Type of capacitor

v. cost?????????????????????vi. Tolerance??????????vii. Size and leakage current

Here are some the applications of capacitor :

1. Filter application :

Capacitors are used as main elements in frequency selective filters. All the filters designed are used for high performance and frequency based applications by selecting the proper components and quality required. Some of the filter topologies are notch, equalization, high pass, low pass, bandpass, band reject and all pass filter.?

2. Reservoir capacitor :

Reservoir capacitors are those who are used to remove AC factor and smooth DC supply. These capacitors are mostly used in power supplies. These capacitors must be Aluminum electrolytic with high capacity and high ripple current capacity.

3. Decoupling / by pass capacitor :

Decoupling capacitors are used in digital electronics to protect the microchips from the electrical noise on power signals. The main role of decoupling capacitor is to reduce noise in circuit and they are placed close to microchip in layout. These capacitors also provide extra energy to the IC and remove disturbances to the logic signal. These capacitors must be ceramic COG or ceramic X7R with small size, low loss but high values.

4. Coupling / DC blocking capacitor :

Coupling capacitors are used in the applications where AC and DC is needed to be separated. These type of capacitors will allow only AC and block DC. Here the capacitance will not affect the coupling applications. But the performance of these capacitors is high if their reactance if high value. These capacitors are used between two different electronic circuit which are connected to each other. For this application must use ceramic COG, ceramic X7R or polystyrene. when its about audio coupling aluminum electrolytic and tantalum can be used.

5. Pulsed power capacitor:

Generally a capacitor is small energy storage component. Large capacitors and capacitor banks are used where lot of energy required within a short period of time. Capacitor banks store lot of energy required within a short period of time for applications like particle accelerator , pulsed laser.

6. Snubber capacitor :

Snubber capacitors are used in the circuits where high inductance load is driven. Snubber capacitors are used in transformers and motor circuits where components charge and discharge quickly, they are also used to avoid spikes in circuit. Mostly in low voltage circuits they are used to protect components from spikes.

Comment if you have something additional to join and any advice or any topic to suggest ...