Free Simple Circuit Diagram
Balance indicator for power supply show if a symmetric power supply is really symmetric or not. With two comparator pairs from a LM339N quad comparator we can make a such indicator. One pair drives the red warn LED3 and the other pair drive the yellow negative(-) and positive (+). The power supply of this circuit is an unregulated voltage. The […]
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A stable voltage source is needed in many calibration process. Most electronic devices are affected by its surrounding temperature. To control all the components temperature by manipulating the surrounding temperature is not easy, but fortunately we can control only the most critical component to produce a stable voltage. The most critical component in a voltage reference is the reference diode, […]
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A signal conditioner for pH meter probe is required to have high input impedance. The signal conditioning of the pH meter probe is done by providing a buffer with gain, offset, and volatge to frequency converter. High input impedance requirement for pH probe while maintaining low cost constraint is given by 3130 CMOS opamp. Output of probe, is amplified by […]
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Most cases of infra-red remote control failure can be detected by detecting the absence of the pulsed transmitted infra red light. It’s very rare that the remote control fail while it is still capable of transmitting the infrared pulse. This condition enable such a very simple tester is easy to build. A simple infrared detector with ac coupling and simple […]
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