Here we have an interesting circuit found in a 1981 publication that causes two LEDs to flash alternately, thus serving as an indicator element for devices of various types. The base of the circuit, shown in the figure, is an operational amplifier 741. The circuit must be powered by a symmetrical power supply with a voltage of 12 V with a current of at least 200 mA. Of course, depending on the type of application for this flasher, you can take advantage of the power supply of the device with which it works.
