| 摘要 |
<p>PURPOSE:To carry out an adequate temperature compensation to the output of a luminous diode for detecting, by amplifying the power of a positive pulse signal with a voltage follower when the oscillator output of a negative pulse is negative, feeding the power and lighting the luminous diode, and making a feedback through a generating circuit of the pluse signal for the feeding voltage to be at constant voltage. CONSTITUTION:The operation amplifier OPA 2 of a pulse transmitter circuit 4 generates a negative pulse, inputs it to the base of a transister Q1 to make in the OFF condition, and the power of a positive signal produced by an operation amplifier OPA4 is amplified by a voltage follower 5 which consists of an operation amplifier 3 and a transistor Q4, so as to feed an output X to a luminous diode 3 through a resistance R1. In this case, a feedback is applied to the follower 5 through the amplifier OPA 4 so as to maintain constant the load voltage X applied to the diode 3. As a result, since the voltage in the regular direction of the diode 3 is low when the temperature is high, the diode current is increased, and since the voltage in the regular direction is high when the temperature is low, the current is reduced so as to compensate the radiating strength.</p> |
