This circuit uses a high brightness LED to simulate a LASER. We found it in a 1991s PE Hobbyst Handbook. The components used are all common.
This conventional astable multivibrator circuit with operational amplifier can be found elsewhere on...
The LDO series (Low Dropout) TPS80 from Texas Instruments (www.ti.com) can provide output voltages...
This circuit was found in a Hands On Electronics from the 80's. The circuit emits an audible alert...