We found this circuit in a Motorola documentation from 1978. The circuit is based on the LM324 operational amplifier, but other amplifiers can be tried out. The diodes are for general use and the frequency is given by 1 / 6.28 RC. With 16k for R and 0.01 uF for C we have 1 kHz. The power supply can be between 6 and 32 V. The 50k resistor can be brought up to 47k.
