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Issue #216 July 2008
Problem 4—How does the oscillator circuit work in the steady state?
Answer 4—Resistor R2 provides a low-current path that charges C3 (through R1) and C7 (through L2). Diode V6 is presumably a Zener or multilayer trigger diode. When it begins to conduct, it turns on BG2 for the first time, discharging C7 through L2. The energy pulse stored in L2 by this then causes current to flow in the primary of transformer B, providing the base drive that gets the main oscillator sequence started. After that, diode V5 keeps C3 discharged so that the startup circuit does not interfere with normal operation.
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