The debate still goes on as to which are better, valves or transistors. We don`t intend to get involved in that argument here. But if you can`t make your mind up, you should try out this simple amplifier. This amplifier uses a valve as a pre-amplifier and a....

This is a 3 stage discrete amplifier with gain control. Alternative transistors such as BC109C, BC548, BC549, BC549C may be used with little change in performance. The first stage built around Q1 operates in common base configuration. This is unusable in....

Here is a very simple three transistor audio amplifier circuit that can deliver 250mW to a 8Ohm speaker. Complementary transistors BC337 and BC227 (Q3 and Q2) are used as the output pair. Transistor Q1 (BC 547) acts as the preamplifier. POT R5 can be used as....

30 incandescent lightbulbs be controlled by my arduino uno on 3 channels (10 bulbs to a channel in parallel). I`ve used the arduino before to control a number of red, green and blue LEDs - I used a simple schematic using three transistors. I`m just not sure....

The car battery charging current is automatically limited to 4. 2A. If there is a 600mV voltage on R1 (4A thru it), then the T1 transistor starts to conduct. Excessive charging current is avoided because the current value on T3 ²s base is limited. The....

This DIY 12V to 220V voltage converter is build with CMOS 4047 that is the main component of this small voltage converter that transforms a 12V DC into 220V AC. 4047 is used as a astable mutivibrator, at pins 10 and 11 will have a symmetrical rectangular....

The fluorescent lamp electronic ballast circuit is composed of the rectifier filter circuit, high-frequency oscillator circuit and output circuit, and it is shown in Figure 3-202. Rectifier filter circuitis composed of the rectifier diodes VDl-VD4 and filter....

This is a DC motor controller circuit, built using transistor TIP31 based on H-Bridge concept. The switch S1 and S2 are normally open, push to close, press button switches. The LED function is to indicate the direction of motor rotation, you may use any....

This capacitance meter circuit is similar with previous meter circuit, but it uses transistors rather than logic gates. Here is the schematic diagram: You...

The photo depicts a completed (bread-barded) locked anti-phase motor controller using general purpose transistors, which allows you to control small DC motors for robotics applications. The big picture problem is that a normal DC motor controller does not....

Uses surface-barrier transistors in arrangement wherein pattern of four on stages is stepped along ring, per mining maximum number of stages in ring lo be much higher than in conventional rings. -W. Carlson, Ring Counter has Increased Count Capacity,....

Designing a true constant-current AA NiMH charger, and want to select a power supply that will be just right. I want a high enough voltage to that the CC transistor doesn`t saturate, yet low enough voltage to reduce the power dissipation in the transistor. I....

A very simple and useful electronic bell circuit can be made using this schematic circuit diagram. This electronic bell circuit can be used as an doorbell or even for an alarm circuit . This electronic bell circuit use just few transistors and other few....

A very simple but very good amplifier unit, with low distortion. A similar modification was used as a preamplifier HAFLER. The quality however of the reproduced sound in all the symmetrical amplifiers regardless of the cost of the necessary materials,....

The 15 w class B audio amplifier circuit shown here is a simple class B audio amplifier based on TL082 op amp, TIP41 and TIP42 transistors. LM833 is a dual amplifier with high scanning speed and low distortion designed specifically for audio applications.....

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The schematic for controlling the motors is split up into three main parts, with each part having a unique functionality. The main parts used and seen in the schematic below are the 18F252, SN754410 and 2N2222 Transistors. Seen at the very top, the....

This is the circuit diagram a powerful LED flasher. High power LEDs are very common in the market now and a 1W high power LED is used here. Transistors Q1 and Q2 are wired as an oscillator which produces positive pulses of width 20ms @ ½ Hz. Transistor Q3....

Simple few transistors generator and transformer A transforms 1. 5V battery voltage to few hundred of volts. This is quite high voltage. Then this high-voltage current passes through a diode, which rectifies current to DC. This DC current is stored in quite....

This Fm rf ability amplifier has 2 transistors from Philips : BLV 10 and BLW 87. The 2 rf transistors assignment in chic C and this fm amplifier has a absolute accretion of 21dB ( 100 X ) and ability 55 65%. One low canyon clarify with 9 apparatus ensures....

This is a long range stable FM transmitter circuit. The circuit is using a LM2950 5V voltage regulator IC comes in TO 92 transistor package, which will provide a stable 5V to the oscillator till the 9V battery runs down to 5. 5 volts, due to which the....

The circuit presented here illustrates the fact that in spite of all kinds of new component and technology, it is still possible to design useful, and interesting, circuits. The circuit is based on two well-established transistors, a Type BF256C and a BF494.....

T1 transistor must be BF200 type (or similar ) and the other transistors can be BF214 type. For high efficiency, the antenna amplifier must be placed at a small distance from antenna. This amplifier circuit can be powered using a power supply that supply an....

A scoreboard in the middle of the room, that one will control from backstage. The scoreboard will have two 3-digit numbers, controlled individually. Whenever the score changes, a little irritating sound should. sound. What is the easiest, more efficient and....

An old ignition module from a 1978 W116 model Mercedes-Benz, and I`m trying to "reverse engineer" it. The original circuit diagram is not available to mere mortals, so I have made one based on the PCB itself. I believe it is, beside being ugly, electrically....

A schematic diagram of the oscillator is shown in Fig. 1. The common-base transistor stage (Q1) provides amplification of the signal in the positive feedback loop. The signal of the positive feedback develops across the resistor R1, this resistor is common....

Portable 230V lamp flasher circuit diagram. The circuit is completely transistorised and battery-powered. The free-running oscillator circuit is realised working with two low-power, low-noise transistors T1 and T2. One of these two transistors is constantly....

Uses 5558 dual opamp and four general-purpose NPN transistors to generate triangle wave that can be distorted by 10k symmetry control to give either fast or slow rise for sawtooth applied as base bias to astable MVBR Q1-Q2. Drain is reasonably low with 9-V....

The 60 Watt linear amplifier is simple all solid state circuit using power mosfet IRF840. The IRF series of power transistors are available in various voltage and power ratings. A single IRF840 can handle maximum power output of 125 watts. Since these....

This decibels meter circuit responds for sound pressure levels from about 60-70 dB(Decibels). That sound is picked up by an 8 ohm speaker, amplified with a transistors stage and LM324 op-amp section. For audio signal input source, a dynamic microphone can be....

This is the schematic diagram of very simple headphone amplifier circuit. The circuit built using two NPN transistors. You can use transistor BC549C or other NPN transistors such as European equivalent: BC548C, BC547C, BC239, 2N5818 or 2N2222 An audio....

The L620x is a monolithic full bridge switching motor driver realized in the new Multipower-BCD technology which allows the integration of multiple, isolated DMOS power transistors plus mixed CMOS/bipolar control circuits and is available in many versions :....