Free electronic circuit design and schematic diagram
Relays are normally operated at current level where it can initiate the mechanical metal contactors movement. After contacts has been established, the current level needed to keep the conductor plates stay attached is actually smaller than the current to initiate it. This power saver circuit seems to have opposite mechanism of surge protector. This circuit provide surge current to initiate […]
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Logic power control of analog regulator can be useful in application where a digital circuit/controller need to control power source, such as in EEPROM programmer or other power controls. This is a circuit provide ON-OFF control for 78xx regulator using digital (TTL or CMOS) signal level. This circuit uses transistors in series with the 78XX regulator, which it’s base is […]
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This is a audio-controlled lamp circuit. This circuit requires low voltage input such as pre-amplifiers, tone control, or general audio line level output. It’s also possible to feed the input with signal from small power amplifier output, or high power amplifier witk low volume level. The characteristic of lamp dimming (incandescent lamp) will look like coming from proportional controller since […]
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Look at the schematic diagram of a circuit below, imagine if the capacitor C1 is not charged and the power is off. There will be no current flow and Q3 will be open. The Base of Q3 will be high and the Base of Q2 low. The circuit is in stable condition and nothing happening. Power will flow through the […]
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Programming old EPROM devices needs high voltage, and this is a circuit of high repetition rate Vpp programming supplies. This circuit is used for memory programming that need higher repetition rate. This circuit produces the Vpp continuously by the switching regulator that runs continuously. To preclude any possibility of inadvertent Vpp output, the switching regulator mus t be turned of […]
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This is a Basic Flash Memory Programming Voltage Supply circuit. This circuit uses LT1072 switching regulator to generate high voltage by driving the L1. R2 and R2 provide DC feedback for this circuit. R3-C2 and C1 control the SC roll-off. This circuit can generate supply of 12V or 12.75V depended on the R1 values. To protect this circuit from the […]
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This is a schematic diagram of Permanent Magnet Motor Control circuit. This circuit is used to control the permanent magnet control. This circuit uses alternistor triac to enhance commutation characteristics because the PM motor is a generator where the standard triac difficult to commutate properly. The full-wave DC rectification is needed for PM motors. Here is the schematic diagram of […]
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