Free Electronic Circuit Schematics » 2N3053

50mW micro audio amplifier circuit with 2N3053

admin — Wed, 07 Jul 2010 14:14:16 +0000

50mW Audio Amplifier

Here’s a little audio amplifier similar to what you might find in a small transistor radio. The input stage is that the voltage is equal to two complimentary transistors which are biased slightly distorted in the leadership that the split between the diodes. Used 3.3 ohm resistor in series with the producers of the transistors to stabilize the bias current, so it does not change much with temperature or with different transistors and diodes. Since the bias current increases, the voltage between the emitter and base decreases, a heat pipe. Input impedance is 500 ohms and the voltage gain is about 5 to 8-ohm speakers connected. Voltage on the speaker is about 2 volts without the distortion and power is in the range of 50 mW. Higher voltage and adding a cooler, the more power output transistors. Circuit draws about 30 mA from a 9-volt supply.

3 to 24 vdc Power supply circuit with Op-amp

admin — Mon, 05 Jul 2010 13:53:03 +0000

3-24volt regulator

The regulated power supply can be adjusted 3 to 25 volts and is current limited to 2 amps as shown, but may be increased to 3 amps or more by selecting a smaller current sense resistor (0.3 Ohm). 2N3055 and 2N3053 transistors should be mounted on suitable heat sinks and the current sense resistor should be rated at 3 watts or more. Voltage regulation is controlled by half in IC 1558 or 1458 op-amp. 1458 may be replaced in the circuit below, but it is recommended that the supply voltage on pin 8 is limited to 30 VDC, which can be accomplished by adding 6.2 volt zener or 5.1 K resistor in series with the eighth pin Maximum DC voltage for 1458 and 1558 are 36 and 44, respectively. Transformer should be able to maintain the required current input voltage at least 4 volts higher than the desired output is, but higher than the maximum voltage op-amp for minimum load.

Power transformer is a center used 25.2 volt AC / 2 amps drive that will provide regulated outputs of 24 V at 0.7 amps, 15 volts at 2 amps, or 6 volts amps 3 amps to the third output is obtained using the transformer tap Wednesday with the switch to 18 volt position. All components should be available at Radio Shack, with the exception of 1558 op-amp.

14Vdc at 2Watt Switching Power Supply Circuit

admin — Sat, 24 Oct 2009 04:51:50 +0000

The work of the power supply is the gain of 2N3053 2N3906 and 2N3904 is fixed internally at 2Watts.

2W switch power supply circuit

It is to compensate the reduction of output power due to low voltage supply the transistor uses the Bridge-Tied-Load principle (BTL) which can provide an output of around 1.5 to 2 W at 14Vdc with a power supply of 6 V.

For the circuit the potentiometer can be used to control the voltage. Capacitor C1 and C2 are meant for filtering the supply voltage if a battery eliminator is used as supply source. For operations using a battery C1 and C2 are no necessary.

The work of the power supply is the gain of 2N3053 2N3906 and 2N3904 is fixed internally at 2Watts.
It is to compensate the reduction of output power due to low voltage supply the transistor uses the Bridge-Tied-Load principle (BTL) which can provide an output of around 1.5 to 2 W at 14Vdc with a power supply of 6 V.

Figure 1 gives a stripboard layout for the 6V regulated power supply shown in figure 1.
The layout does not include the transformer block, so the input to the board needs to be 6V AC from a suitable transformer.
The layout includes space for two optional 2-way screw terminal blocks to make connecting up the power supply easier.

If the input voltage is 6V AC, you will be able to draw 1A from the power supply. For the maximum input voltage of 14V you will be able to draw 2W.

14 Volts 2Watt Switching Power Supply Circuit With 2N3053

admin — Wed, 01 Jul 2009 15:54:32 +0000

: Switching Power Supply 14 Volts 2W Circuit

For this electronic project in small switching power supply Schmitt trigger oscillator is used a transistor of switching system which is currently a small inductor.

The energy in the inductor while the transistor is switched on and in the charge circuit when the transistor off.

The output voltage is dependent on the load and is provided with a Zener summarizes oscillator when the voltage to about 14 volts.

More or less high voltage can be minimized by adjusting the voltage divider provides the Zener.

The efficacy is about 80% with a high Q inductor.

Power Off Relay Timer

admin — Sat, 13 Jun 2009 05:16:07 +0000

The two circuits below illustrate opening a relay contact a short time after the ignition or ligh switch is turned off. The capacitor is charged and the relay is closed when the voltage at the diode anode rises to +12 volts.

Power Off Relay Timer Circuit

The circuit on the left is a common collector or emitter follower and has the advantage of one less part since a resistor is not needed in series with the transistor base. However the voltage across the relay coil will be two diode drops less than the supply voltage, or about 11 volts for a 12.5 volt input. The common emitter configuration on the right offers the advantage of the full supply voltage across the load for most of the delay time, which makes the relay pull-in and drop-out voltages less of a concern but requires an extra resistor in series with transistor base. The common emitter (circuit on the right) is the better circuit since the series base resistor can be selected to obtain the desired delay time whereas the capacitor must be selected for the common collector (or an additional resistor used in parallel with the capacitor). The time delay for the common emitter will be approximately 3 time constants or 3*R*C. The capacitor/resistor values can be worked out from the relay coil current and transistor gain. For example a 120 ohm relay coil will draw 100 mA at 12 volts and assumming a transistor gain of 30, the base current will be 100/30 = 3 mA. The voltage across the resistor will be the supply voltage minus two diode drops or 12-1.4 = 10.6. The resistor value will be the voltage/current = 10.6/0.003 = 3533 or about 3.6K. The capacitor value for a 15 second delay will be 15/3R = 1327 uF. We can use a standard 1000 uF capacitor and increase the resistor proportionally to get 15 seconds.