shorts

Found 2 Results for shorts.

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1. Bench - Type Continuity Checker
Since the VOM has a multitesting capability and is handy to carry around, it's a popular piece of equipment in the workshop. This means frequent changing of selector-switch function and range settings which can often be inconvenient and lead to meter damage if not done carefully. The test probes themselves often make accurate measurement of an operation requiring three hands. One way to make continuity checks quicker and more efficient is to build a separate checking device for this purpose. The continuity checker is ideal for this purpose and can be built inexpensively. Electrically, the device is quite simple. The key component is isolation relay FR-101 (available from ALCO Electron Products, Inc., North Andover, Mass.), which combines an isolated stepdown transformer and a sensitive low-voltage relay in a single unit. With 110V ac applied to terminals 3 and 4 of the four-terminal barrier strip, 30V is induced into the isolated circuit as measured at test receptacle J and across terminals 1 and 2 of the terminal board. When an appliance with its power switch in the on position is plugged into test receptacle J, a continuous circuit is created. This shorts the isolated circuit of the checking device, allowing current to flow through relay coil K and activate the low-voltage relay. Lamp I (a low-wattage lamp available in electrical-supply stores) in the relay's primary winding circuit will then light, indicating good continuity in the appliance. It can be seen that the test leads applied across the plug prongs of the appliance cord, or across isolated portions of the circuit, will achieve the same result. Although this checker is limited in that it cannot give resistance readings and must be connected to a 110V outlet, it serves to give a quick yes / no circuit test without the need of setting dials and often without the need of handling probes. Constructed in a minibox equipped with test leads and a test receptacle, this device can be a great convenience in the fix-it shop. The reader should bear in mind, however, that it is not suitable for checking transistor circuitry. The continuity tester can be used for checking the operation of wall-mounted furnace thermostats whose contacts can become pitted or contaminated. The thermostat is disconnected from its circuit and tested independently by connecting test leads to its two screw terminals.
http://www.fun-home-projects.com/electrical_projects/​tools/​bench_type_continuity_checker.html

2. Diode / Triac Tester
When closed, S2 shorts the diode. If a diode is being tested, when S2 is closed lamp 12 should light with about half the brilliance of II since it is conducting only half the time.
http://www.fun-home-projects.com/electrical_projects/​tools/​diode_triac_tester.html

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