General Amplifier Testing
Keywords: universal op amp test
Using the comparative characteristics of the operational amplifier input, the production of operational amplifier testers can quickly and accurately determine the quality of the measured transportation, which is very useful in component selection. The author guides the student training process. Use this small instrument to pick the purchase of the calculation amplifier {including partial disassembly}.
Circuit Principle Tester Basic Design Idea is to be tested as an arithmetic amplifier (IC1, IC2, IC3, IC4) into a comparator structure. When V + >v, Vout is a positive power state. Close to VCC, light emitting diode VD1 illuminates. When V + V +. VD2 illuminates. Resistors R5, R6, C1, C2 constitute a power split circuit. Divide the 9V power supply into 2 * 4.5V. Make VE = 0V, VDD = + 4.5V, VEE = -4.5V. Meet the requirements for the operation of the operational amplifier dual power supply. R7-R14 in the circuit is a series resistance in the input, and the purpose is to test the multi-operation amplifier. One of these operational amplifiers does not affect other operational amplifiers after the input is damaged, and the circuit design uses two 8-foot DIP sockets. To meet the test of universal models, double and four op amps. The test instrument principle see the figure below. Be
The debug tester of the op amp tester has two eight feet and one fourteen foot integrated circuit DIP socket, combined with the light-emitting diode and power supply. The socket 1 is used to measure the single operation, and the 7 foot is powered. 4 foot power supply is negative, 2 pin inputs. 3 pin input is 6 pin output. The socket 2 measures dual op amp, 8 feet are power supply, 4 feet are power supply, 2, 6 pin input negative. 3, 5 pin inputs. 1, 7 feet are output. The socket 3 measures the four-shift, 4 feet are power positive, 11 feet are power supply, 2, 6, 9, 13 foot input negative 3, 5, 10, 12 pin inputs 1, 7, 8, 14 "pin is output. In the circuit diagram, IC1, IC2, IC3 are given as the principle. In fact, the connector 1, socket 2, and socket 3 should be connected above, as long as the wiring is correct, hardly use it. R5, R6 should be as equal to it. Be sure to be virtual. R5, R6 is due to the power fission resistance and a current limiting resistor of the light emitting diode. Can be selected between 200-510 Europe. Small the resistance, shining, power consumption. The resistance is large, weak, and it is not easy to observe. R1, R2, R3, R4 should be as soon as possible. Guaranteed to be "ground". The resistance is selected in the middle of 10K-100K, and the linear potentiometer of the same order is selected, and a scale line is made in the middle to adjust. (The value of the resistors on the circuit diagram is for reference only. When the production can be made according to the existing resistance in the hand, the VD1-VD8 selects the different color light emitting diode to facilitate distinguishing. Turn off the power before measurement, insert the integrated circuit to be tested, single, double op amp, four operations to insert the corresponding socket, pay attention to the position of the pin, then close K to adjust the RP observation, according to the luminous tube The status is good or bad, and the test is turned off, and the integrated circuit is removed. Note You cannot charge the integrated circuit to avoid damage to the integrated circuit.
The op amp test instrument uses the plug-in, inserted into the socket DIP1, and the power is turned on, the VD1 illuminates: upward adjusts RP, VD2 light, when the RP is in the intermediate position. The output is zero, VD1, VD2 is lowered. When performing a dual op amp test, insert the dual op amp (IC1.IC2) into the socket DIP2, adjust the RP, VD1, and VD3 down. RP, VD2, VD4 is adjusted upward; when tested for four-operated (IC1, IC2, IC3, IC3). Inserted into the socket DIP3, and the RP is adjusted down. VD1, VD3, VD5, VD7 illumination; adjust RP upwards. VD2, VD4, VD6, VD8 illuminated. You don't have to look for midpoints in the test, as long as you observe the changes in the lighting tube, you can judge the advantages and disadvantages of its comparative characteristics. For multi-played tests. RP should be adjusted slowly. In order to observe the light emitting brightness of the light-emitting diode and the difference in lighting time to determine the consistent characteristics of its multi-play. If there is only one state when the RP is adjusted in the test, it does not change, indicating that the op amp has lost comparative characteristics and cannot be used.
Summary author uses this small instrument to place LM741. CA3140, CA3130, NE5534. Double op amp LM358, MC1458, TL062. TL082. Four transportation LM324, TL084, and LM747 were tested. The effect is ideal. Especially for screening of the disassembly element, it is very useful.
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