| 摘要 |
The start circuit uses a ferrite core as a high voltage transformer in which the primary winding is supplied with 20 KHz power and provides output current of 25 mA or greater one. The input voltage rectified by a bridge type rectifier (1) is stored in a condenser (C4) for triggering a SCR (SCR2) through a diode (TD). When the SCR is turned on, a dividing resistor (R7) voltage drops and a condenser (C3) triggers a SCR (SCR1) simultaneously. At this time, the secondary winding provides high voltage to start the Neon lamp and the induced voltage is generated at the primary winding also. The induced voltage biases a transistor (Q3) to bypass the condenser (C4) voltage and a condenser (C2) provides inverse voltage to the SCR5(SCR1-2) to turn off them.
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