We found this circuit in a 1986 documentation. It uses only LEDs, batteries, resistors and the power supply which can consist of 4 batteries or a 9V battery. The basic circuit uses two-color LEDs.
In the figure we have the basic application of an LM3900 transconductance amplifier, as suggested by...
This one is from an 80's EDN. Transistors can be general purpose types. The frequency is...
This circuit uses a PLL4046 oscillator to excite a piezoelectric ceramic. The circuit is from an...