100µF Electrolytic Capacitor
A polarized, high-value capacitor typically used for power-supply smoothing and slower timing circuits.
How this component works
A capacitor stores charge on two conductive plates separated by an insulator (dielectric). Its capacitance, measured in farads (F), determines how much charge it can hold per volt applied.
In DC circuits, a capacitor blocks steady current once charged but allows current to flow briefly while charging or discharging — this is the basis of timing circuits and debounce filters. In AC circuits, a capacitor's impedance falls as frequency rises, which is why capacitors are used to filter out high-frequency noise or block DC while passing AC signals.
Common types differ mainly in construction: ceramic capacitors (small values, no polarity) and electrolytic capacitors (larger values, polarized — must be wired the right way round or they can fail).
Common Use Cases
- Smoothing capacitor after a rectifier to reduce ripple on a DC supply
- Timing capacitor for a slow 555 astable or monostable circuit
- Bulk energy storage to supply brief current spikes (e.g. a motor starting)
Frequently Asked Questions
What happens if I connect it backwards?
Reverse-biasing an electrolytic capacitor breaks down its internal oxide layer and can cause it to overheat, vent, or fail outright — always match the marked negative stripe to the lower-voltage side of the circuit.
Why is it so much bigger in value than a ceramic capacitor?
Electrolytic construction packs far more capacitance into a small package than ceramic can, at the cost of polarity, tolerance, and higher parasitic resistance — which is why it's used for bulk storage rather than high-frequency filtering.