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The circuit below requires a double pole, double throw relay in conjunction with a single transistor to allow toggling the relay with a momentary push button. One set of relay contacts is used to control the load, while the other is used to provide feedback to keep the relay activated or deactivated. Several push buttons can be wired in parallel to allow toggling the relay from different locations. In the deactivated state, the relay contacts are arranged so the 1000 uF capacitor will charge to about 2.7 volts. When the switch is closed, the capacitor voltage is applied to the transistor base through a 560 resistor causing the transistor to turn on and activate the relay. In the activated state, the relay contacts are arranged so the 3.3K resistor and 560 ohm resistor provide a continous current to the transistor base maintaining the activated state. While in the activated state, the capacitor is allowed to discharge to zero through the 1K resistor. When the switch is again closed, the...

Output form Transistor Amplifier The below fig shows the common emitter transistor amplifier. There are two ways of taking output from the transistor amplifier. The output can be taken either across R C or across terminals 1 and 2. In either case the magnitude of output is the same. Suppose if we take the output across load resistor R C in the collector circuit i.e. Output = Voltage across R C = I C R C      …………………… (4) This method of taking output from collector load is used only in single stage amplifiers. The output can also be taken across terminals 1 and 2 V CE = V CC – I C R C            …………………. (5) From this V CC is a D.C. Voltage and cannot pass through capacitor C C therefore only varying voltage I C R C will appear across terminals 1 and 2.  Output = I C R C From expression (4) and (5) it is clear that the magnitude of output is the same whether takes output across collector load or ...

Most photovoltaic cells are made of silicon chip above which there resides a very thin layer of noble metal through which around 1% of photon particles enter the material and activates electron flow. Here I’m showing how to make one simple solar panel using transistor. [ ]

This is the electronic siren schematic diagram which used 2 transistor BC547 and BC557. The siren is powered by 9V battery or power supply adapter and use 8 ohm speaker to produce the sound. The siren is controlled by the touch plate switch. If you touch the plate, then this electronic siren will be activated.  2 Transistor Electronic Siren Circuit Diagram

Description. This is of course the simplest electronic code lock circuit one can make. The circuit uses one transistor, a relay and few passive components. The simplicity does not have any influence on the performance and this circuit works really fine. The circuit is nothing but a simple transistor switch with a relay at its collector as load. Five switches (S0 to S4) arranged in series with the current limiting resistor R2 is connected across the base of the transistor and positive supply rail. Another five switches (S5 to S9) arranged in parallel is connected across the base of the transistor and ground. The transistor Q1 will be ON and relay will be activated only if all the switches S0 to S4 are ON and S5 to S9 are OFF. Arrange these switches in a shuffled manner on the panel and that it. The relay will be ON only if the switches S0 to S9 are either OFF or ON in the correct combination. The device to be controlled using the lock circuit can be connected through the relay terminal...

PROGRAMMABLE UJT OR PUT It is not an ordinary unijunction Transistor. But the V-I characteristics is almost similar to an ordinary ujt. Programmable ujt is a four layer P-N-P-N device with a gate connected directly to the sandwiched N-type layer. The term "Programmable" is applied because the interbase Resistance Rbb, the intrinsic stand off ratio and peak point voltage Vp as defined in UJT can be programmed to any desired values through external base Resistors Rb1 and Rb2 and the supply voltage Vbb. WORKING OF PROGRAMMABLE UJT Figure indicates that the anode-gate Junction is Forward biased when the anode becomes positive with respect to gate. When this occurs, the device is turned ON. The anode to cathode voltage Vak then drops to a low level, and the device conducts heavily until the input voltage become too low to sustain conduction. It is seen that this action stimulates the performance of a UJT. The anode act as Emitter ofthis unijunction Transistor. SCHEMATIC SYMBOL OF...

Using only four transistors in the quasi-complementary amplifier configuration, this transistor power amplifier circuit can deliver 90W of power into 4 ohm loads and at low cost. As shown in the transistor power amplifier circuit there are no expensive components in this circuit, except the power transformers and speakers. As shown in the diagram there are no expensive components in this circuit, except the power transformers and speakers. Input stage is formed by this two current driver directly raised a pair of transistors of the output stage. Transistor level end (2N3055) mounted on a heat sink to keep the lifetime of these devices. Supported by one source (of 80Vcc) at the output of the final stage, before the speaker, a capacitor is placed to block DC current, and just skip the audio signal. The power supply circuit 90 W audio power amplifier must be sufficient to provide current 1.5A per channel audio. Thus the power required to operate the stereo 3A and 6A is required for the fo...

A transistor amplifier must have a DC biasing circuit for several reasons. Especially, we will need two separate voltage supply to provide the desired class bias voltage to the emitter-collector and emitter-base. In fact it is actually only done in certain applications, but found that biasing voltage can be obtained separately from a single supply. Second, the transistor is very sensitive to temperature and creates a condition called thermal runaway. Thermal runaway will quickly destroy the bipolar transistor, because the collector current out of control quickly and will improve to the level of damage and the temperature will rise if there is no stabilizing the temperature at the amplifier to eliminate this effect. A common class for refractive surgery is a Class A, AB, B, and C. All of these classes use the same arrangement of the components to her on the operation of the DC bias transistor Q-point or different. Location of the variation bias point Q for different amplifier classes Cl...

This tester is primarily meant to test bipolar transistors. It can indicate the type of the transistor as well as identify its base, collector and emitter pins. The circuit is very simple. The direction of current flow from the terminals of the transistor under test (TUT) is indicated by a pair of LEDs (green-red). An npn transistor produces a red-green-red glow, while a pnp transistor produces a green-red-green glow, depending on the test point that connects to the terminal of the transistor. Emitter and collector are differentiated by pressing pushbutton switch S1 that actually increases the supply voltage of the circuit by about 5.1V. At the heart of the circuit is IC CD4069 (IC3), which oscillates and produces pulses required to test a pair of transistor leads for conduction in both the directions. Different combinations are selected by an arrangement of counter CD4040 (IC1) and bilateral switch CD4016 (IC2). Fig. 1 shows the circuit of the bipolar transistor tester. A pair of LEDs...