The figure shows how to implement an alarm buzzer in an LM3914 to warn about crossing the scale limit. The circuit can use other types of warning.
This circuit indicates when a 28 V lamp burns, lighting a neon lamp with higher voltage. The...
This circuit, which can be used on an optical link, is suggested by the Texas Instruments...
We found this circuit in a 1992 Popular Electronics. The circuit has an optical sensor with LED...