Capacitors play an essential role in the stable operation of digital electronics by protecting the noise sensitive microchips from the power signal that can cause abnormal behaviors.
The capacitors used in this application are called decoupling capacitors and should be placed as close as possible to each microchip to be most efficient because all circuit paths act as antennas and will raise noise from the environment. Disconnection and condenser capacitors are also used in any area of a circuit to reduce the overall impact of electrical noise.
Coupling or DC Blocking Capacitors
Since capacitors have the ability to pass AC signals while blocking DC, they can be used to separate the AC and DC components of a signal. The value of the capacitor does not need to be precise or precise for the coupling, but it must have a high value since the reactance of the capacitor drives the performance in coupling applications.
In circuits where a high inductance load, such as a motor or a transformer, is induced, high thresholds of transient power can occur because the energy stored in the inductive load is suddenly discharged, which can damage components and contacts. Applying a capacitor can limit or block the voltage across the circuit, making safer operation and circuit more reliable. In the case of less power circuits, a locking technique may be used to prevent unwanted radio frequency interference (RFI) that may cause abnormal behavior in circuits and cause difficulties in obtaining certification and approval of products.
Pulsed Power Capacitors
At the most basic capacitors, batteries are effectively low and offer unique power storage capabilities beyond those of chemical reaction batteries. When a multitude of energy is needed in a short period of time, large condensers and condenser banks are a superior option for many applications. Capacitor banks are used to store energy for applications such as pulse lasers, radars, particle accelerators, and rail rails. A common application of the pulsed power capacitor is in flash on a disposable photo camera that is then charged and discharged rapidly by the flash, providing a high current pulse.
Resonant or Tuned Circuit Applications
While resistors, capacitors and inductors can be used to make filters, certain combinations can also lead to amplification of the resonance of the input signal. These circuits are used to amplify signals at resonant frequency to create high voltages from low voltage inputs such as oscillators and regulated filters. In resonant circuits, you must be careful to select components that can survive the stresses that components see on them or that will fail quickly.
Capacitive Sensing Application
Capacitive sensing has recently become a common feature in advanced consumer electronic devices, although capacitive sensors have been used for decades in a variety of applications for positions, humidity, fluid level, manufacturing quality control and acceleration.
The capacity sensing capability detects a change in the local environment capacity by a dielectric change, a change in the distance between the capacitor plates or a change in the area of a capacitor.
Some safety measures with capacitors should be taken. As components of energy storage, capacitors can store dangerous amounts of energy that can cause fatal electrical shocks and breakdown equipment even if the capacitor has been disconnected from power for a considerable period of time. For this reason, it is always a good idea to discharge capacitors before working on electrical equipment.
Electrolytic capacitors are prone to violence under certain conditions, especially if the voltage on a polarized electrolytic capacitor is reversed. Capacitors used in high power and high voltage applications may also fail violently because dielectric materials decompose and evaporate.
A capacitor can store electricity when it is connected to its charging circuit. And when disconnected from the charging circuit, it can dissipate the stored energy so it can be used as a temporary battery. Capacitors are commonly used in electronic devices to keep the power supply while the batteries are being changed. (This prevents the loss of volatile memory information.)
Conventional electrostatic conductors provide less than 360 joules per kilogram of energy density, while capacitors using the developing technology can deliver more than 2.52 kilojoules per kilogram.