Is it safe to use a polarized electrolytic capacitor as a low-cost alternative to a non-polar electrolytic in a small-signal (-0.7 < V < 0.7) bipolar filtering application? One expert has suggested that polarized caps work fine in both directions at low voltages, but we would like to be sure that there are no serious drawbacks. Thanks.
Your expert is correct. Polarized aluminum electrolytic capacitors can withstand up to 1.5VDC of reverse bias without being seriously damaged.
Please explain for the formula for
Temperature Rise within a Capacitor.
Put simply. The temperature rise formula is the rms AC current( ripple) squared times the ESR of the capacitor at the operating frequency divided by a thermal constant multiplied by the surface area of the capacitor.
IF the calculated temperature rise is greater than 10C then the capacitor is being overstressed and will eventualy fail sooner than it should.
EIA dictates that ESR must be measured using the bridge method using a test frequency of 120 Hz or 1kHz depending on the type of capacitor so the easiest way to measure ESR is by using a LCR bridge..
Are there special considerations for electrolytic capacitors used at high altitude ( 1/8 atmopshere ) operation ? We are using AFA surface mount series or similiar.
Most Aluminum electrolytic capacitors can be used up to 20000 feet without any problems. Above 20000 feet measures should be taken to prevent the capacitor from failing. Typically leaded parts are used and have their end seals covered with epoxy to pevent contamination and prevent the electrolyte from being forced out of the container.
Is it safe to use a polarized electrolytic capacitor as a low-cost alternative to a non-polar electrolytic in a small-signal (-0.7 < V < 0.7) bipolar filtering application? One expert has suggested that polarized caps work fine in both directions at low voltages, but we would like to be sure that there are no serious drawbacks. Thanks.
