The voltages found in Haiti and Iran are significantly different.
Some appliances are compatible with multiple voltages. To find out if your appliance is one of them, check the appliance label and/or instruction booklet.
This appliance is only compatible with a single voltage as only one voltage (120V) is printed on the label.This appliance is compatible with a range of voltages as it shows two voltage figures with a dash in between them. In this example, the appliance may be plugged into any outlet ranging from 100 to 240V without a voltage transformer, though a socket adaptor would still be needed if the sockets don't match.This appliance is compatible two voltages as it shows two voltage figures with a slash between them. Appliances displaying labels like this will have a physical switch located on them somewhere, allowing you to switch between the two voltages shown here. In this example, the appliance may be plugged into an outlet of 115V or 240V (provided the switch is in the correct position) without a voltage transformer, though a socket adaptor would still be needed if the sockets don't match.
Is your appliance compatible with the voltage used in Iran (230V)?
If your appliance is not compatible with multiple voltages, you will need a transformer to adjust the voltage input when using your appliance in Iran.
Considerations
Frequency of Electrical Current
The frequency of electrical current found in Haiti (60Hz) differs to that found in Iran (50Hz).
Most equipment is not affected by differences in frequencies. Some exceptions are:
Electric clocks: Some electric clocks use the frequency of electrical current to measure time. If the clock is designed for one frequency, but used with another, time shifts could be experienced.
Appliances using motors: If there is a motor load associated with an appliance, the frequency governs the speed in revolutions of the motor. This could mean that the motor will spin faster, or slower than intended and could have a detrimental effect in the appliance's operation. This is of particular concern in power tools and other machinery that uses motors, so if you must use these, you should seek access to a frequency converter.