Easy Ways To Understand The Filter Capacitors In Electronic Circuits Have you ever wonder why you will find so many capacitors in electronic circuit board? They are all scattered during the complete electronic board. You might see mica capacitors, ceramic capacitors, tantalum capacitors, aluminum electrolytic capacitors, paper capacitors and etc. Them all in the circuit have a function and you will find widespread applications in the electrical and electronics fields. Some of the common situations by which capacitors are employed are as follow: Electric Field-Power factor correction;-Motor start and run; and -Welding (stored energy in capacitor discharged rapidly) Electronic Field - Behave as filter to eliminate ripple in power supplies; - As inter stage signal coupling capacitors- A capacitor will not pass DC, but an AC signal should go through; - Tuning resonant circuits, oscillator circuits; - Decoupling in power supplies and amplifiers; - Within timing circuit; and - As waveshapers and filters In the current article I'm planning to covers capacitor behave as filter to remove ripple from power supplies. When the AC signal from output transformer passed through diodes it would become an uneven DC. A filtering section is used to smooth out this uneven DC signal. Usually, the filter includes one or more capacitors. The capacitors are then placed between the DC line and ground. The value of the capacitors is chosen carefully to give the filter circuit a particular timing constant or TC. This TC measures how fast the circuit responds to changes in the voltage level. If the circuit has just the right timing constant, it could act to smooth the output voltage, and after the voltage leaves the filter stage, the majority of the variations or "ripple" ought to be removed. The AC has been changed into an easy DC. If the filter capacitors fail either upsurge in ESR reading or lose a number of its capacitance, the AC signal is likely to be allowed to stay with the DC, creating a signal that will be noisier than it will it. This unwanted noise signal can create problems in electronic circuit. If it happen in computer monitor power supply, the bad capacitors could cause power to blink, low power, voltage shutdown, no display, intermittent display problem ands many more. So you understand why each time when a monitor has the complaint like above, I'd first check all of the secondary side filter capacitor with my ESR meter. If all capacitors checked okay 224 ceramic capacitor I would then proceed to some other circuit. That's one among my troubleshooting methods. Next, have you seen all the small blue caps around a signal board? Those small value caps (usually 0.1uf 50 v or 104) may also be used to get rid of noise from electronic circuit. Then how about the event of big filter capacitors we've just mentioned above-aren't they already removed the unwanted signal? You will want to one filter capacitor is enough for each DC line voltage? The clear answer is that the big filter capacitors (large value) at the secondary side of power supplies is to smooth the
DC and remove unwanted lower frequency noise. Meanwhile the little blue resin coated ceramic disc capacitor is more effective in shorting very good frequency noise spikes to ground and to preventing it from getting back in the ability supply line and planing a trip to other circuits.