This reader with TTL logic compatible output uses an LM139 comparator. The circuit was found in the 1994 National Semiconductor Linear Applications Handbook.
This circuit was originally designed to operate with the CB18751E which transmits its signals via...
This TTL circuit was found in an American documentation from the 80s. The components are common in the...
This circuit is from an 80's documentation. It makes use of two SCRs with current capacity...