Free electronic circuit design and schematic diagram
If you have to provide a fan to cool your audio power amplifier final transistor, it better to turn it off when it’s not needed. This solution is good since you don’t have to hear the fan noise when you play the music with low level volume at night, the power transistor won’t get hot. When you start turning your […]
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This circuit is line powered flasher, can be used in any application, and Christmas lamp is one of the example. Look at the circuit’s schematic diagram below: The control for triggering the SCR is done by Q1, Q2 and related resistors. The timing depends on R1,R2 & C1. To change flashing frequency don’t modify R1 and R2 values: set C1 […]
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You can use this circuit to give auto trigger for your secondary flash light. You don’t have to worry about wiring for the control, because using this circuit your secondary flash will be automati8cally triggered when it receive the light signal from the primary flash. Look at the circuit’s schematic diagram below. The inductor 68mH is connected in parallel with […]
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If you need a negative supply for op-amp or just need negative bias voltage while operating from a single supply voltage (for battery operation for example), this circuit helps providing the negative supply for you. The circuit is based on charge pump driven by 555 switching circuit. Here is the schematic diagram: The negative voltage produced by this circuit is […]
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This circuit provide automatic current limiting up to 8.4A. Unlike current limiter that uses only a resistor, this current limiting circuit doesn’t drop the voltage, or at least keep the voltage drop at minimum, until a certain current amount is exceeded. This current amount limit is adjustable from 1.4 A to 8.4A using a potentiometer. You can modify the component […]
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This tone control circuit use very popular Baxandall configuration, a simple circuit configuration that provides boost and cut control in continuous manner. This circuit is very cheap to build, and it’s commonly implemented in commercial product. Here is the circuit’s schematic diagram: The transistors can be substituted by any general audio transistors with small current gain more than 100 (BC547, […]
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This audio power amplifier circuit is simple and robust, and use discrete component available on many electronic part stores. The final transistors use 2N3055 and MJE2055. Here is the circuit’s schematic diagram: The MJE2055 is an npn transistor, but the configuration with TIP42A make the whole combination of TIP42A and MJE2055 are seen as pnp transistor. This audio amplifier circuit […]
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