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This rugged power supply is based on the popular LM338 3-pin voltage regulator. The LM338 is capable of supplying 5 A over an output voltage range of 1.2 V to 32 V with all standard protections like overload, thermal shutdown, over-current, internal limit, etc., built in. In this power supply, some extra protections have been added to make it particularly suitable for use with low to medium-power portable and mobile VHF/UHF (ham) and 27 MHz transceivers. Diodes D4 and D5 provide a discharge path for capacitors C1 and C2. Diode D8 protects the supply against reverse polarity being applied to the output terminals. Capacitor C1 assists in RF decoupling and also increases the ripple rejection from 60 dB to about 86 dB. If junction R1-R2 is not grounded by switch S1A, transistor T2 starts to conduct, causing the regulator to switch to zener diode D7 for its reference voltage (13 V). The PSU output voltage will then be 12.3 V. Normally, T2 will be off, however, and the PSU output voltage is ...

A good way to spend a relaxing afternoon is to be in a quiet place with just the right amount of sun or shade, drinks within reach and listening to your favourite songs on MP3 or CD. You doze off and by the time you wake up again the audio equipment has dropped silent due to flat batteries. What a pity! The simple circuit shown can prevent this embarrassing situation by de-actuating a relay when no audio signal is detected for about two seconds. Auto-off for Audio Gear Circuit Diagram The circuit consists of a sensitive LM358 based comparator, IC1A, which keeps monostable IC2A (a 4538) triggered as long as an audio signal is detected at the input. Via coupling capacitor C1 the circuit takes its input signal from the ‘hot’ side of the loudspeaker or headphones in your audio gear. The monostable will time out 2 s after being triggered, the delay being deter-mined by R6 and C3.

Implementation of Cust omised SCADA for Cartoner   Packaging machine for Cost Effective Solution Abstract –   In Factory Automation   engineers are looking for the use of Visual Basic for the implementation of SCADA applications for several reasons.    Most of the SCADA applications require a very less number of user input parameters and data logging, monitoring and trending functionalities to be visualised by the user.    In Industrial environment, there are times when traditional SCADA based solutions provide most of the functionality but at a much higher cost than budgets allow for small OEM customers. By utilizing Visual Basic's integrated event based user interface design and database connectivity    functionality like SQL and adding off-the-shelf plug-in’s like ActiveX controls or DLL    or MSCOMM components to produce frontend graphics, trending, communication, and alarming. Developers, OEMs, integrators, and users can create...