| 摘要 |
PURPOSE:To detect the presence or absence of the coins at both the dial turning time and the dial releasing time via the dial turn detection circuit and the dial transmission detection circuit. CONSTITUTION:When the dial is turned, short contact DS is switched on to give flashing to luminous element EL1. Thus photo detector PT2 is switched off, and voltage Vpt2 turns to the H level. This change is differentiated by capacitor C6 and resistance R13, and the light emission is given to EL1 via transistor Tr6. If the coin exists at the side of element EL1, FF2 is not set. Accordingly, SCR is off to enable the dial transmission. Impulse contact Di is switched off while the dial is being turned, and capacitor C5 is switched on via Zener diode ZD2 and inventer IN1. Thus, EL1 is made to emit the light to detect the presence of the coins. If no coin exists there, SCR is turned on to block the dial transmission. |
