This circuit is a simple oscillator. It’s frequency is in the range 35 kHz – 60 kHz and it’ s adjustable.
D1 is infrared LED
Values of components are shown in schematic
All resistors are 0.25w and all capacitors are 16v
With RV1 you can adjust frequency
For best result circuit work with 9v battery
Pcb size is 2.5cm*3cm.