Abstract: A strobe alarm circuit which utilizes an optocoupler in the DC-to-DC converter portion of the circuit for repetitively connecting and disconnecting an energy-storing inductor across a DC power source. The light-emitting diode portion of the optocoupler is connected in parallel with a resistor network which continuously monitors the current flowing through the inductor; when the inductor current has attained a value at which the sum of the voltages developed across the resistors of the network is sufficient to turn on the LED, the switch portion of the optocoupler is turned on and disconnects the inductor from across the source. A thermistor connected in parallel with one of the resistors of the resistor network compensates for changes in values of the elements of the optocoupler which may occur due to temperature changes.