We found this circuit in an 80's manual. The same configuration can be adapted to make use of modern operational amplifiers. The power supply is symmetrical.
A square signal of about 1 kHz is produced by this astable multivibrator. Frequency is determined...
This sophisticated source has a digital indication, and the output voltages are adjusted in...
This circuit was found in a Poptronics of the 90's. The components can be changed to the desired...