A 555 timer running at 1 kHz. Based off of measured component values. Play around with the resistor values and the capacitor attached to the resistors. The output frequency is determined by the following equation. Where the values in this circuit are chosen starting at the top resistor being R1 and going counter clockwise to the capacitor attached to ground.
f = 1.44/(R1+(2*R2))*C)
f = 1.44/(1.25k+(2*70.9k))*9.85nF)
= 1020.54 Hz
