This circuit is from the 80's, using an integrated of the time. The circuit serves as a reference, as this type of dialing is no longer used today.
The HA2620 integrated circuit used in this comparator is from the 80's, but the setting can be...
This circuit uses the Linear Technology LT6505 and was found in a 2005 manual. The circuit is for 24 V...
This interesting circuit of the American publication Electronics Handbook Volume XIII 1993 shows a...