A 160V capacitor is able to replace a 100V capacitor in most cases, so long at the voltage rating of the capacitor is higher than that of the circuit and the two capacitors are of the same type. That being said, a 160v 47microfarad is designed to be 47microfarad at 160V and lower voltages MAY change its actual capacitance. So if the circuit calls for a 100V capacitor, it is ideal to stick to that, but it will likely work with a higher rating.

Cases where a minor change in capacitance might be an issue:

• RF Applications
• Timing applications
• Audio applications (on signal side)
• Signal processing

Places where a minor change in capacitance is likely a non-issue:

• Power regulation
• Power filtering
• Ripple prevention

In short, if the capacitor is used as a “battery” the circuit will likely be unaffected by the change, but if the capacitor is used for filtering with timing based upon its capacitance the circuit may be affected by the change.