This circuit is from an old manual from National Semiconductor (Now Texas), using the LM2877 not very common today, but it admits an equivalent. The circuit operates with voltages from 6 to 24 V and the trip values are given in the table next to the diagram. The original circuit drives indicator lamps, but LEDs with resistors in series can be used. The input impedance is 4 M ohms.
| Clique na imagem para ampliar |
