With this circuit it is possible to vary the resistance by adjusting the mark/space reaction of the 555. The circuit was found in the November 1989 Radio Electronics magazine.
We found this adapter in a 1970s American documentation on instrumentation. It is suitable for analog...
The Texas Instruments LM5178 Buck-boost controller is capable of operating in the 4.2 to 55 V (60...
The circuit shown in the figure is recommended for applications where a visual indication is...