ICL8038 and XR-2206 can help you build a Function Generator or Wavform Generator. It is needed along with the Oscilloscope and Power Supply on the Workbench.
The ICL8038 waveform generator is a monolithic integrated circuit capable of producing high accuracy sine, square, triangular, sawtooth and pulse waveforms with a minimum of external components. The frequency (or repetition rate) can be selected externally from 0.001Hz to more than 300kHz using either resistors or capacitors, and frequency modulation and sweeping can be accomplished with an external voltage.
See the Full page with parts list at my Website – Function Generator using ICL8038.
Use in Phase Locked Loops – Its high frequency stability makes the ICL8038 an ideal building block for a phase locked loop as shown in Figure 9. In this application the remaining functional blocks, the phase detector and the amplifier, can be formed by a number of available ICs (e.g., MC4344, NE562).