| 摘要 |
<p>PURPOSE:To start a hot wire type flowmeter without the use of an external power source by providing a power source adapted to always supply power starting from the closing of a key switch through a B-grade push-pull circuit, an operation amplifier having a transistor at the output thereof and a resistance. CONSTITUTION:In an operation amplifier 90, a B-grade push-pull circuit is made up of a transistor 901 and a transistor 902 and a transistor 904 acts to absorb a constant current at an output terminal V01. When a key switch is closed, a voltage is applied to a resistance 87 and after regulated with an operation amplifier 90, applied to a positive input terminal thereof of a hot wire type flowmeter to start it.</p> |
