Abstract: An apparatus connectable between a current source and an electrical load for indicating current flow through the load above a threshold level. The indicator includes two negative temperature coefficient (NTC) thermistors, and a neon indicator lamp. The first thermistor is connected directly in series with the electrical load and the second thermistor is connected in series with the neon lamp. The thermistors are packaged together by an epoxy resin, which thermally couples the thermistors so that both thermistors operate at substantially identical temperatures. Current flow above the load's operational threshold level causes the first thermistor to heat to an equilibrium temperature well above the ambient temperature. At this elevated equilibrium temperature, both resistors have extremely low resistance values. The low resistance value of the second thermistor permits maximum current flow to the neon lamp, which illuminates the lamp.