Three useful analogue building blocks based on the translinear principle applied to MOS transistors operated in weak-inversion, are presented. A four-quadrant parametric current amplifier, coming in both a global biasing and local biasing flavor, and a two-quadrant current divider are derived from a basic translinear loop composed by 4 transistors. The resulting circuits are very compact and precise. Simulation results for all the circuits and measurements of a realized prototype of a two-quadrant current amplifier are provided. Low-voltage, low-power performances with input currents ranging over three decades and relative errors smaller than 3% are achieved.