My Light Diagram

Is is easy to test the polarity of a circuit’s point whether it is positive or negative by using the tester circuit featured here. The tester circuit has a high input impedance (around 1 megaohms) to avoid loading the point being tested. In testing sensitive points however, (inputs of opamps), the input impedance must be taken into consideration. The opamp 741 is the core of the polarity indicator circuit. Its non-inverting input is used to test the points for polarity. It has a gain of around 150 which enables it to test low voltage levels. The test result is displayed through the two LED’s D1 and D2. D1 lights up by positive polarity and D2 lights up by negative polarity. Take note that the pin profile on the diagram is based on the TO-5 package profile.

This is a very basic dual polarity power supply circuit diagram, it also called symmetrical power supply or split power supply. It just need the following components: A Center Tapped Transformer Diode rectifier 4 units (or diode bridge 1 unit) Electrolityc capacitor 4 units The value of each component are depending on your needs. For example, if you need dual polarity power supply to supply an 100W amplifier circuit which need 32V voltage supply, then the recommendation are as follow: Transformer: 3A center tapped transformer 24V – 0 – 24V. Diode rectifier 1N5402 : 4 units Electrolityc capacitor (elco) 4700uF/50V – 6800uF/50V : 4 units With above component’s value, the power supply will be able to handle 100W output load. Circuit note: Based on above scheme, the ground is connected to the “E” mark. The “E” is the center of the transformer. In center tap transformer, there are some outputs that have same values (24V for example) and an output which has 0 output. The ground (E) shou...

What do you think of building a simple LED tester, so you can test the integrity of the components before soldering directly to the PCB. It reduces the task of testing the meter components using the circuit with LED gives an indication about the good or bad condition of the component. Test Multiteste LEDs - Polarity - Continuity - Resistance Circuit When a component is placed in the circuit and establishes electrical continuity T1 receives base current through R1. When T1 conducts, the green LED turns on and off the red LED. This indicates that the component to be tested is good. If the component is bad, will not have electrical continuity and T1 remains off. In this state only the red LED light indicating that the component is bad.   Polarity Connect the red end of the positive range to the circuit board and to test the black edge point. Circuit board under test to be lit Green LED ON - positive feed. Green LED off and red LED - or no negative supply voltage. Continuity Connect bo...