Modern wave generators use many different circuits and generate such outputs as SINUSOIDAL, SQUARE, RECTANGULAR, SAWTOOTH, and TRAPEZOIDAL waveshapes. These waveshapes serve many useful purposes in the electronic circuits you will be studying.
The Clapp oscillator is one of several types of electronic oscillator constructed from a transistor (or vacuum tube) and a positive feedback network, using the combination of an inductance (L) with a capacitor (C) for frequency determination, thus also called LC oscillator.
This is a very simple circuit utilising a 555 timer IC to generate square wave of frequency that can be adjusted by a potentiometer.
This is yet another method to generate low frequency output pulses. The circuit uses an inexpensive under-voltage monitor IC and a couple of cheap MOSFETs.
Oscillators may be classified by name, such as Armstrong, Hartley, Colpitts, or by the manner in which dc power is applied. An oscillator in which dc power is supplied to the transistor through the tank circuit, or a portion of the tank circuit, is said to be SERIES FED.
It could easily be modified to produce pulse frequencies from about one cycle per minute to a maximum of about 10KHz. It draws only about 1uA from a 3v battery.
drive heavy loads, the duty cycle is adjustable from 25 to 75%; and feedback minimizes the drift
you can turn flip/flop ICs into low current oscillators. This schematic shows you how.