BC547 Transistor Datasheet and Circuit Schematic
The BC547 is an NPN Epitaxial Silicon Transistor. The BC547 transistor is a general-purpose transistor in a small plastic packages. It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors.
BC547 Transistor Technical Specifications
The BC547 transistor is an NPN Epitaxial Silicon Transistor. The BC547 transistor is a general-purpose transistor in a small plastic packages. It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors.
The BC547 transistor is an NPN bipolar transistor, in which the letters "N" and "P" refer to the majority charge carriers inside the different regions of the transistor. Most bipolar transistors used today are NPN, because electron mobility is higher than hole mobility in semiconductors, allowing greater currents and faster operation. NPN transistors consist of a layer of P-doped semiconductor (the "base") between two N-doped layers. A small current entering the base in common-emitter mode is amplified in the collector output. In other terms, an NPN transistor is "on" when its base is pulled high relative to the emitter. The arrow in the NPN transistor symbol is on the emitter leg and points in the direction of the conventional current flow when the device is in forward active mode. One mnemonic device for identifying the symbol for the NPN transistor is "not pointing in." An NPN transistor can be considered as two diodes with a shared anode region. In typical operation, the emitter base junction is forward biased and the base collector junction is reverse biased. In an NPN transistor, for example, when a positive voltage is applied to the base emitter junction, the equilibrium between thermally generated carriers and the repelling electric field of the depletion region becomes unbalanced, allowing thermally excited electrons to inject into the base region. These electrons wander (or "diffuse") through the base from the region of high concentration near the emitter towards the region of low concentration near the collector. The electrons in the base are called minority carriers because the base is doped p-type which would make holes the majority carrier in the base
BC547 Transistor Circuit Schematic Symbol
BC547 Transistor Pinouts
BC547 Transistor Sources
The BC547 is very common and manufactured by ON Semi, Fairchild, and NXP. They can be purchased in small quantity for $.03 to $.20 depending on variation Mouser, Digikey both stock the BC547 samples.
Project: Economic Battery Sufficiency Tester with BC547 Circuit
Battery level indicators generally detect the voltage levels of the batteries to give a result. So, tester circuits must not be a heavy load during the measurement process. This tester circuit draws very low current. A short duration of LED bright will show you the battery has still enough voltage level to operate devices. This light brights due to the discharging of C1 on D1 LED, this happens only when the battery provides enough voltage. When you close the S1 switch, Tr1 transistor makes C1 to discharge through R3 current limiter. Minimum required battery voltage level can be determined by using voltage divider R1/R2. Values of R2 and R3 must be calculated as shown below;
R2 = (0.6 x R1) / (Vbmin - 0.6) Ohm and R3 = (Vb - 1.4) / 0.2 ohm
For example, for 6.5Vb(min) value (to test a 9V battery) R2 must be 10k and R3 must be 39 ohm. R4 must be between 10k and 1M. For higher values of R4, circuit becomes more economed after abic but this causes lenghten the test period. When R4 is 100k, battery can be testout 10 seconds.
Project: Headlights Timer with a BC547 Transistor
Pushing on P1 allows C1 charging to full 12V battery supply. Therefore Q1 is driven hard-on, driving in turn Q2 and its Relay load. The headlights are thus activated by means of the Relay contact wired in parallel to the vehicle headlight switch. RL1 remains activated until C1 is almost fully discharged, i.e. when its voltage falls below about 0.7V. The timing delay of the circuit depends by C1 and R1 values and was set to about 1min. and 30sec. In practice, due to electrolytic capacitors wide tolerance value, this delay will vary from about 1min. and 30sec. to 1min. and 50sec. An interesting variation is to use the inside lamp as a command source for the timer. In this way, when the door is opened C1 is charged, but it will start to discharge only when the door will be closed, substituting pushbutton operation. To enable the circuit acting in this way, simply connect the cathode of a 1N4002 diode to R1-C1 junction and the anode to the live lead of the inside lamp. This lead can be singled-out using a voltmeter, as it is the lead where a 12V voltage can be measured in respect to the vehicle frame when the lamp is on.
Project: Voltage Controlled Switch with a BC547 Transistor
This voltage controlled switch circuit operates when a voltage level which is previously adjusted is applied to the input. Circuit is designed for 24V supply but can be used in a range of 18V-36V. Voltage level which triggers the circuit can be adjusted by P1 potentiometer. A stabilized voltage is applied to this potentiometer through zener diode and Tr5. When the input voltage level exceeds this value TR1 starts conducting and afterwards Tr2, Tr3, Tr4 transistors conduct and relay switches on. Switch S1 that is connected to relay, carries the signal from Tr3 to Tr1 through R1 and keeps Tr1 conducting. When the input is short circuited, D1 diode keeps the circuit operating and you can omit it if you want.
BC547 Datasheet and Related Keywords
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