Excellent video demonstrating why bypass and decoupling capacitors are so important for signal integrity and also EMC compliance – a must watch!: https://www.eevblog.com/2018/05/19/eevblog-1085-bypass-capacitors-visualised/
Category: Capacitors
Parallel Connecting Capacitors
There are several reasons why you often see capacitors, particularly electrolytics, connected in parallel: EEVblog #742 – Why Electrolytic Capacitors Are Connected In Parallel
ESR
ESR = Equivalent Series Resistance Lowering ESR Use lower value capacitors connected in parallel. This gives you the overall capacitance you want and the overall ESR value works just as for normal resistors wired in parallel. ESR and Heat ESR is resistance so if your capacitor has lots of current flowing in / out / etc then the […]
Electrolytic Capacitors
Electrolytic Capacitors Life The life of Electrolytic capacitors drops significantly with temperature which is why they are rarely found in automotive applications.
RC Filter
RC calculation T=RC, so: Time Resistance Capacitance or mS Kohms uF or Seconds ohms F The result gives you 1T. This is 1 time period. So for 1000uF and a 1K resistor T = 1000mS For charging and discharging a capacitor: 1T 63% 2T 86.5% 3T 95% (this tends to be the default usage with […]
Ceramic Capacitors
Multilayer ceramincs are great for applications where voltage is constant (ie. you are smoothing off a voltage). However they are not good for use inline for AC voltages (i.e. audio and AC signal filters). The reason is that ceramic capacitors will give a piezo electric effect to an AC signal, which causes noise. For audio […]
Tantalum Capacitors
Tantalum capacitors have a couple of important design advantages:- They can be excellent at removing noise (for instance placed across power rails) and improving the EMC performance of a circuit. They are physically small The main downside is that they are more expensive than say an equivalent electrolytic capacitor. Voltage It is important to derate […]