Abstract: A coin discriminator comprises photoreceivers along a vertical drawn from an infed coin run chute whereby screening and illuminating the photoreceivers from a photoemissive source permit coin diameter identification. Two coils on either side of the chute detect the coin alloy. Coin thickness is determined using a stepshaped transversal section across the chute track where the step risers lie opposite the photoreceivers which transmit a signal word identifying the infed coin diameter and thickness. This signal word is compared with memorized words representative of acceptable coin dimensions. If the dimensions are acceptable, a combination of impedances in a bridge circuit incorporating the coils is selected in terms of the alloy corresponding to the acceptable dimensions. If the bridge balances for this combination as the coin rolls between the coils, the coin is accepted.