Heart of Stone (1985) from Tuna |
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SPOILERS: Heart of Stone (2001) is a serial killer/thriller film. There is a ritualistic murder of a co-ed during the opening credits, then we see Angie Everhart preparing a birthday party for her daughter, who is about to start college. After the party, Everhart tries to seduce her own husband, who is frequently away on business. At this point in the film, about 5 minutes in, based on the man's character and the way they introduced him, I figured he must be the killer. |
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From there, they do their level best to convince the audience that someone else is guilty. A younger man seduces Everhart, then tricks her into lying to give him an alibi for the time of a second ritual killing. He stalks her, we learn that he is a former mental patient, and eventually see him kill several people. Nearing the last five minutes of the film, Everhart's daughter has killed the young man, and I was still convinced that the husband was the serial killer. Sure enough, I was right. |
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network) across the primary side of the transformer reduces stress on the switching MOSFET.
The PCB layout, often included with the schematic, can be improved to provide better heat dissipation for the switching IC. 3. Practical Tips for Modifying the Schematic
+--------------------+ | HT2812H | | | +-----------+---HV VCC---+---> To VCC Supply | | | | | | Pri. Winding | | of Transformer | | | | | +-----------+CS FB---<-----+ From Aux. Winding | | +---CS (Sense) | | | [Rcs] | | | GND | (Primary GND) | | +-------------------+ | | Secondary Side | (Isolated Output) | +-------------+-------------+ | | | +-------+ | +---+D1 (Schottky)+-----> +5V Out | +-------+ | | | | | +-------------------+ | | | +----------+ | +---+C1 (390µF)+---+ | | +----------+ | | | | | | | +---L1 (Inductor) | | | | | +----------+ | +-------+C2 (Cap)+----+ | +----------+ | | | | | GND GND GND (Secondary GND) | | AC Input | | | +--+---+ | | F1 | | +--+---+ | | | +-----+-----+ | | MOV EMI | | | (Varistor)| | +-----+-----+ | | | +-----+-----+ | | Bridge | | | Rectifier | | | (MB10F) | | +-----+-----+ | | | +-----+-----+ | | Bulk Cap | | | (Filter) | | +-----+-----+ | | | +-----+-----+ | | Snubber | | | Network | | +-----+-----+ | | | +-------------------------+ | | | +-----------------+ | Primary Winding of Transformer | To HV Pin of IC
), always disconnect power and discharge the high-voltage capacitor before working on the circuit. wxdc12003 schematic better
The high-voltage alternating current enters via the L (Line) and N (Neutral) pins. It passes straight into a basic bridge rectifier, smooths across a high-voltage 4.7µF capacitor to reach roughly 310V DC, and enters the flyback switching circuit driven by the controller IC. An optocoupler bridges the isolation barrier to provide voltage feedback to the controller. 4 Concrete Upgrades for a Better Custom Schematic
The high-frequency AC pulse from the transformer's secondary side is rectified by a high-speed Schottky diode (such as an SB540 or equivalent). A basic Pi-filter or parallel capacitor network (usually a solid-state or high-temperature electrolytic capacitor) levels the output voltage to its nominal 5V or 12V rating. 3. Why the Standard Factory Schematic Fails
When working on a , keep these practical points in mind: network) across the primary side of the transformer
) components to ensure the 5V output remains closer to its target value.
An integrated PWM controller (often similar to Viper series or similar integrated MOSFET ICs) manages the switching frequency.
This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later. The high-voltage alternating current enters via the L
If recreating the PCB (via software like GitHub KiCad Modules ), deliberately broaden the copper fills connected to the drains of the switching transistor and the secondary Schottky rectifier. Treat the PCB traces as an integrated heatsink.
Now, the real value: using your newfound understanding of the schematic to improve the default design.
| Parameter | Stock | Better Target | |-----------|-------|----------------| | Max continuous current | 1.5A (reliable) | 3A (reliable) | | Output ripple (20MHz BW) | 120mVpp | <30mVpp | | Efficiency at 12V->5V, 2A | 78% | >90% | | Thermal rise (3A, 5 min) | +65°C | +35°C | | Load transient overshoot | 250mV | <50mV |
: A high-frequency transformer provides safety isolation between the high-voltage AC input and the low-voltage DC output. Output Filtering