This circuit was found in the November 1966 issue of Electronics Now magazine. It uses an LDR as a sensor and has a Bargraph scale with the well-known LM3914.
The integrated circuit of this pulse generator is 4093 and the frequency can be between a fraction of...
The figure shows how to implement a stage with an emitter follower. The stage has high input...
This circuit is an improved version of the previous ones with the LM3914. We found it in the March...