The frequency of this circuit depends on C1 and, for the indicated values, it is 1 kHz. Equivalent operational amplifiers can be used, and the power supply must be symmetrical.
This circuit is from a 90s Popular Electronics. It appears elsewhere on this site. Q1 can be any...
This circuit was found in a 90's Electronic Design. It takes advantage of the nonlinearity...
In the figure we have an example of an application of a monostable in which the shot is made by...