Abstract: A hybrid integrated circuit (121) is coupled to an adapter circuit (151) to facilitate trimming of film resistors (126, 127, 128 and 129) formed on the hybrid circuit. The adapter circuit (151) includes a plurality of safety resistors (156, 157 and 158) which are to be selectively added in series with the film resistor (126) to be trimmed. A computer (145) facilitates the measurement of (1) the resistance of the untrimmed film resistor (126) and (2) the gain of the hybrid circuit (121). Depending upon the measured gain, the safety resistors (156, 157 and 158) are selectively added in series with the film resistor (126) to establish a basic resistance value. Thereafter, the film resistor (126) is trimmed by a laser (144) until the resistance value of the film resistor (126) is equal to the basic resistance value. Other safety resistors are used during the trimming of the remaining resistors (127, 128 and 129).