Abstract: A reactant composition includes: a diol component; a diacid-derived component; and a modifier represented by the following formula (I): wherein R1, R2, and R3 independently represent H or a methyl group, and at least one of R1, R2, and R3 is a methyl group. A polyester made from the reactant composition is also disclosed.

Abstract: A light emitting diode (LED) circuit is provided. A light emitting diode (LED) circuit includes an alternating current (AC) source, a rectifier, a voltage-limiting circuit, and an LED module. The AC source provides an AC voltage, and the rectifier generates a first rectified voltage according to the AC voltage. An upper limit of the first rectified voltage is substantially restricted at a rated voltage by the voltage-limiting circuit, and the voltage-limiting circuit generates a second rectified voltage according to the first rectified voltage, in which the second rectified voltage is lower than the rated voltage. The LED module receives the second rectified voltage. Thereby, when the AC voltage is unstable, fluctuation of current flowing through the LED module can be substantially reduced.