Posts Tagged ‘CA3140’

High impedance DC Voltmeter by IC CA3130

The MOSFET input of the CA3140 makes it ideally suited for use in a high impedance DC voltmeter. Switch S1 is the range selector. The input impedance is limited to 10M by the resistors used in the voltage divider, but this is still a very acceptable value. Before switching on for the first time, the mechanical zero adjustment of the 100m A instrument should be set so that the pointer rests just below zero on the scale. The unit is then switched on and with the input shorted, TR1 is adjusted until an exact zero indication is obtained. The TR2 is used for calibrating the meter so that the full scale deflection in the three ranges is 1V, 10V and 100V. The supply voltage can be anything between 8 and 20V. The current consumption is less than 6mA at 12V. The accuracy of this voltmeter depends mainly on the quality of the 100mA instrument and the care with which the unit has been calibrated.

Source ::http://users.otenet.gr/~athsam/dc_voltmeter.htm

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Simple Timer by CA3140 + NE555

This be the circuit sets the time to model is simple,at can fix the time had long ago and have tall good accuracy. By use pillar equipment be IC CA3140 for fix time mouth and NE555 perform sound electric bell origin. By we can fine time value done to a turn VR1 can fine since 10 second arrive at 3 hour. When the time expires will have an electric bell that a loudspeaker. For the equipment that should choose specially. Be C1 100uF 16V values should are a kind Tantalum. Because tall quality more Electrolytic. The moderately but if no enough replace can sir. Request friends have fun the circuit sets the time this please sir.

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Power Supply 5-13V with IC 7805 & CA3140

Circuit 5-13V Power Supply with IC 7805 + CA3140
The DC Variable Voltage Regulator 3-15V 1A Circuit be easy circuit. because of use IC 7805 usual have volt regulate 5V 1A. When use IC CA3140 join in as a result make fine Voltage output get with by fine R1 get the value Volt about 3-15V and give current get 1A be the same. The detail is other request friends see in the circuit better.