Weekend Project

A 1.5 V Minimal Art Receiver

Here is a direct-conversion receiver powered by a single 1.5 V battery cell. It is designed for operation with high-impedance headphones. Mixing takes place in the oscillator stage: the antenna is coupled through an input transformer that is in series with the quartz crystal. The antenna side of the transformer ("sec" in the schematic) has 3 turns for the best 50-ohm match. A 5 kΩ trimmer is used for optimum performance. The VXO frequency is pulled by a small capacitor, which gives a tuning range of a few kHz. The AF output signal is surprisingly loud and clear.