A current mirror circuit arrangement wherein an output current is provided by an output transistor and coupled between the base electrode of the output transistor and a reference potential is a series combination of a resistor and a diode. Signals are fed to the base electrode of the output transistor from a voltage supply via an emitter follower circuit and a resistor is connected across the diode so as to share current with the diode to increase its impedance at low current values and consequently to improve the overall linearity of the output current input voltage characteristic.
A signal transmission system for transmitting, in particular, an ignition timing correction signal in an ignition timing control system for an internal combustion engine includes an ignitor for producing an ignition timing signal in response to an ignition signal from a distributor, and the ignition timing signal is further corrected by the ignition timing correction signal calculated in a computer based on engine operating conditions sensed by sensors. The computer includes a voltage-current converting circuit which converts the ignition timing correction signal in the form of a voltage signal into a current signal corresponding thereto and supplies the current signal to the ignitor through a signal line connecting between the computer and the ignitor. The ignitor includes a current-voltage converting circuit to convert the current signal from the computer into a voltage signal corresponding to the current signal which indicates the correction of the ignition timing.
