General Electric suggests this circuit in an 80's documentation. The circuit makes use of PUTs that are not common components today. Note the timing components that may change.
This Hughes circuit is from 1968. Equivalent modern components can be used. The input impedance is...
An interesting application in case of needing to supply an operational amplifier or a very low...
This VCO with the CMS 4046 was found in the August 1994 Electronics Now magazine. The frequency is...