This amplifier was found in Burr-Brown documentation from the 90's. The gain can be programmed by resistor Rg as per the table given in the diagram. The power supply must be symmetrical.
This circuit was found in an old Electronic Design. It makes use of sidacs and operational not very...
This 2009 circuit is a bilateral call warning. Easy to build, using light communication between two...
This circuit for shunt motors was found in an American 1980s documentation. The SCR should be rated...