Free Simple Circuit Diagram
We can use this basically a high gain amplifier with feedback circuit to cause the LED flash at rate determined by the 10u and 330k resistor. Before insert the unknown transistor, remove one of the transistor. The LED flash when it’s NPN with pins as shown in the photo. Remove one of the transistors to turn the unit off. [Source: […]
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All types of transistors including Darlington and power will be tested in this project. Connect the 9v battery around the other way at points A and B to test PNP types. The transformer in the photo is a 10mH choke with 150 turns of 0.01mm wire wound over the 10mH winding. Then, the two original pins (with red and black […]
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Circuit below is a very sensitive 3-transistor amplifier using a speaker transformer. This can be wound on a short length of ferrite rod as show above or 150 turns on a 10mH choke. The biasing of the middle transistor is set for 3 V supply. During idle conditions and the quiescent current is just 5mA, the second and third transistors […]
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We can use the circuit below to maintain the level of water in the header tank within prescribed limits. A 3HP submersible bore pump which has a high starting current is controlled by this circuit, necessitating a solid-state relay sufficient to take the starting load. The upper and lower water sensors in the tank are connected with two Darlington transistors, […]
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