Free electronic circuit design and schematic diagram
This is an oscillator circuit that can be used for calibrating frequency counters, amateur receivers and frequency meters. This circuit is called 2MHz standard with dividers circuit. This circuit uses two crystals, 100kHz and 2 MHz. Here is the schematic diagram of the oscillator part of the circuit: This circuit is then can be combined with two 7490 decade counter […]
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Monitoring battery voltage can be important in some application. Some battery monitor will be simply a continuous LED lamp which is dimming according to the voltage level. Here is presented monitoring circuit that flashing, which is more noticeable than simple dimming the light intensity. At 1.2V, the LED begin flashing, and the flashing rate will increase as the voltage increase. […]
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The circuit of off-air monitor for SSB transmitter can be built by using combination of detector product with the crystal oscillator. This circuit is used for testing the audio at one point within band. The quality of audio will still constant, if loading and tuning of SSB transmitter are same over rest of band. The LC circuit will resonated to […]
Read moreThis is a intake air temperature (IAT) sensor video. This video shows how the IAT sensor works. This sensor has two terminal, the ground terminal and reference voltage terminal. The ground is connected to the pin 5 of OBD-2 and the 5V refence signal is supplied by ECM. This sensor is maybe located in intake air deck. Here is the […]
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This is a speech processor circuit that can be used in communication radio circuit. This circuit consist of two sections, they are amplification and compression or dipping. The combination of these processing will improve the SSB communication intelligibility and provide higher average level while avoiding clipping. The 100K pot is used to adjust the compression degree, as well as adjusting […]
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The linearity of 555 IC is sufficient to make 1 second precision, and this circuit employs the feature in this design. This timer step circuit can generate a timing steps from 0 to 59 s in 1-s intervals. Here is the schematic diagram of the circuit :
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This is a over/under voltage monitor circuit. This circuit is used to monitor Any potential from 1 to 15 V. If there is a undesirable variation was occurs, two lamps will flash. The voltage differential fro lamp turn off and turn off is about 0.2V at any setting. Low and high set points are independent of each other. The type […]
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