8 Channel D/I Card for RS232 Schematic Circuit Diagram

The author is a student at the Electronics Department, Technological Educational Institute of Piraeus, Greece. This project is a card with eight optically isolated TTL-compatible inputs for external connection to the serial port, which communicates through the RS-232 protocol. On this card, you will look in vain for a UART or microcontroller chip because the[…]

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Zero suppressor for IC17106

Many people are irritated by the superfluous zero that precede a number on, for instance, a liquid crystal (Lc) display. To them ‘1’ is clearer than ‘001’. In systems where the ICL7106 display is used, this irritation may be removed by the present suppress. Both the backplane (BP) and the segment of a 1CL7106 arc[…]

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Low-drop diode

At high currents, many silicon diode has a forward voltage of 1 V or more. There are types whose drop at currents of up to 2-3 A is limited to 0.5-0.6 V, but even that may cause unacceptably high losses. The circuit described here offers a possible remedy. The cathode, C, of T1, a SIPMOS[…]

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test probe

General Purpose Test Probe

The compact test probe is made from five transistors, three LEDs, a zener diode, and three resistors. It enables rapid ‘measurement’ of voltage levels at digital gates, fuses, diodes, batteries, and others. Of course, it does not provide absolute values, but rather a good indication of correct operation or otherwise. Measurements are carried out with[…]

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