An electronic oscillator is an electronic circuit that produces a periodic, oscillating electronic signal, often a sine wave or a square wave. Oscillators convert direct current from a power supply to an alternating current signal. They are widely used in many electronic devices. Common examples of signals generated by oscillators include signals broadcast by radio and television transmitters, clock signals that regulate computers and quartz clocks, and the sounds produced by electronic beepers and video games.
Very Simple Reed Relay Oscillator . This can be "self oscillating". Only you need an axial inductor mine is 250 Ω resistance & Reed Switch inside the inductor an white Led DC3.2-3.4V 20mA 10mm Round. It is amazing to drive a super bright led only with 3ma but i would say that it is High Efficiency. If you like my demonstration Please click the "like" button, subscribe my channel, and share this with your friends... To support my "work" every little bit helps! Watch the "ADS" THANKS... Please feel free to post your comment! Stay Tuned and Enjoy!