Guitar and Bass Compressor

This is a simple guitar and bass compressor. It's only possible because of the performance of the NE5532 opamp, which can drive the low impedance of the rectifier without any sign of distortion.  VR1 controls the limiting threshold, and the output level from U1B is set at about 3V RMS (sinewave) or ±6V peak with programme material.  The gain of the first stage can be increased if needed, by reducing the value of R4.

Parameters of Nonlinear Delayed Circuit

This is a design schematic circuit diagram for parameters of nonlinear delayed circuit. This circuit is based on LM 324 as brain of the controller. The nonlinearity is built up of the transistor T 1 , the adjustable amplifier OA 1 and the resistors R 2-R 7. Electronic components: delay line: bucket brigade line MN 3011 with 3328 stages, triggered by MN 3101 (both National Panasonic); OA 1 :LM 324N; C = 660 pF; R 1 = 470 k,R 2 = 100 k lin., R 3 = 22 k, R 4 = 4.7k,R 5 = 10 k,R 6 = 1k,R 7 = 47 k;T 1 BC 238C. This the figure of the circuit schematic.

Tips for Increasing Bass Sound for Car System Sounds

To improve the quality of the car's sound system is to replace standard audio devices. The speaker is the audio device that is most often replaced, the reason for the user is because the sound quality standard speakers are not maximal. In addition to the poor sound quality, if the music volume is loud the speaker sound is not strong enough. 

Let's look at this article how the Power Amplifier & Subwoofer makes the power more maximal The second reason is because replacing speakers is more practical and installation is faster. The market can easily be bought at a fairly affordable price. But do not just buy speakers if you do not understand the specifications of the speaker, not even better, the results of the sound that is not in line with expectations. 

Park Aid Circuit

Here’s a design circuit for designed as an aid in parking the car near the garage wall when backing up. LED D7 illuminates when bumper-wall distance is about 20 cm., D7+D6 illuminate at about 10 cm. and D7+D6+D5 at about 6 cm. In this manner you are alerted when approaching too close to the wall. This is the figure of the circuit;

How is this circuit work? IC1 forms an oscillator driving the infra-red LED by means of 0.8mSec. pulses at 120Hz frequency and about 300mA peak current. D1 & D2 are placed facing the car on the same line, a couple of centimeters apart, on a short breadboard strip fastened to the wall. D2 picks-up the infra-red beam generated by D1 and reflected by the surface placed in front of it. The signal is amplified by IC2A and peak detected by D4 & C4. Diode D3, with R5 & R6, compensates for the forward diode drop of D4. A DC voltage proportional to the distance of the reflecting object and D1 & D2 feeds the inverting inputs of three voltage comparators. These comparators switch on and off the LEDs, referring to voltages at their non-inverting inputs set by the voltage divider resistor chain R7-R10.

Part of the components:
R1_____________10K   1/4W Resistor
R2,R5,R6,R9_____1K   1/4W Resistors
R3_____________33R   1/4W Resistor
R4,R11__________1M   1/4W Resistors
R7______________4K7  1/4W Resistor
R8______________1K5  1/4W Resistor
R10,R12-R14_____1K   1/4W Resistors

C1,C4___________1µF  63V Electrolytic or Polyester Capacitors
C2_____________47pF  63V Ceramic Capacitor
C3,C5_________100µF  25V Electrolytic Capacitors

D1_____________Infra-red LED
D2_____________Infra-red Photo Diode (see Notes)
D3,D4________1N4148  75V 150mA Diodes
D5-7___________LEDs  (Any color and size)

IC1_____________555  Timer IC
IC2___________LM324  Low Power Quad Op-amp
IC3____________7812  12V 1A Positive voltage regulator IC

555 IC PWM Controller Circuit: Grounded and Ungrounded Load

While keeping the oscillator frequency relatively stable, this 555 based PWM controller features almost 0% to 100% pulse width regulation using the 100k variable resistor. To give a frequency range from about 170Hz to 200Hz , the frequency is dependent on the 100k pot and 100n. This is the figure of the circuit;

You can see the charging and discharging of the 100n cap is done through output pin 3, and this provide a push-pull symmetric drive for easy pulse-width setting. You can see two versions, the left side for grounded load, and the right side for ungrounded load. The grounded one use pin 7 to drive the transistor, while the ungrounded one use the same push-pull output pin3, this difference is needed because wen need an inverted phase to provide consistent potentiometer scale on both version. [Circuit source: talkingelectronics.com]

Backlight Driver for WLED Display Circuit

This is a design circuit for WLED-display backlight driver circuit. This circuit can be used to power WLEDs by replacing the voltage-feedback network with a series current-sense resistor, R3, and the WLED strings. This circuit uses The TPS6108x that drive some series WLEDs in parallel for backlighting larger displays. This is the figure of the circuit;

The feedback of this circuit is The voltage across the current-sense resistor. This feedback provides regulation. This circuit uses 1.2-V feedback voltages. The power lost of this circuit because of R3 is Plost= Iwled*Iwled*R3 = 1.2V*Iwled. The TPS6108x converters is equipped with an SS pin that can provide variable soft startup for boosted voltage regulation applications. Beside that, The SS pin can be used to lower the FB-pin reference voltage and to reduce sense-resistor power loss in aWLED current-regulation application. The FB-pin reference voltage can be lowered by connecting a resistor, R1, from the SS pin to GND. WLED current can be calculated by following equation:

Iwled=(Iss*R1)/R3

Analog dimming is provided by A second resistor, R2, that is connected with the FET and Q1 in series connection and parallel connection with R1. Those connections will lower the regulated FB-pin voltage across the sense resistor.

[Schematic circuit source: Texas Instruments Application Note]

Nonvolatile STANDBY/ON Switch Circuit

STANDBY/ON switch below is appropriate for applications (industrial and telecom, for example) in which the circuitry must remember its state (STANDBY or ON) after a power failure that occurs when there is no operator. Because the state can be lost if leakage current drains the battery, we can not just rely on an alternative approach based on battery (or supercapacitor) and flip-flop. The other way is involving the use of a microcontroller and EEPROM, but software and a provision for startup time is required. A stand-alone EEPROM has an awkward interface for this application.

An electronically programmable voltage reference (IC4, DS4305) is used as a single-bit nonvolatile memory cell, that’s the idea. This device can be reprogrammed minimum of 50.000 times to remember the state of the STANDBY/ON switch, high or low output voltage. This is the figure of the circuit.

IC1 (MAX6766) is a kind of low-dropout (LDO) linear regulator with RESET output and the wide input-voltage range can be extended up to 72V. The control button (STANDBY/ON pushbutton) bounces can be eliminate by a uP (IC2,MAX6468). This IC supports the programming of IC4 by increasing the pause length between pulses. An inverter with Schmitt-trigger input(IC5) is driven by IC4 output, which in turn drives the gate of transistor Q2 to control the main power supply. [Circuit schematic source: MAXIM Application Note]

Stepper Motor Circuit Using 74194

This is the circuit for the driver to adjust the motor speed at STEPPER motor. This circuit can drive a motor 12v to 24V. This circuit is based on 74194. The test series are placed differently and show SN7474 in logic block form and LED lights are used to indicate the motor coil is removed. This is the figure of the circuit.

STEPPER motor circuit uses IC 555 astable oscillator produces a series of clock pulses fed to Pin 11 of integrated circuit SN74194. Every time the clock pulse goes HIGH (positive) in the country in the SN74194’s HIGH OUTPUT terminal (PIN’s 12, 13, 14, 15), transferred either UP or DOWN y one place. Referring to the “Stepper Motor Driver Waveforms” diagram. Shift direction is controlled by a switch S2.

When S2 is in the middle position OFF HIGH-state output will remain in last position and the motor will be stopped. When the base of Q6 is a shift to PIN LOWER 12-15 – 14 – 13-12. When the base Q7 is a shift to PIN LOW 12 – 13 – 14 – 15 – 12. Direction of the shift pulses determine the direction of motor rotation. The pulses from the OUTPUT’s of SN74194 four segments are fed Driver ULN2003. When the input of a segment is HIGH, it will activate the Darlington transistor and OUTPUT will conduct current through one of the motor coils. As the roll motor turned ON in order to follow the motor rotates these steps.
[Circuit source: home.cogeco.ca]

Driving Capacitive Load Circuit

This is a one design circuit for low impedance loads circuit using driving the capacitive loads. This circuit is combine the high output current required to slew large capacitances with appropriate frequency compensation. This circuit is based on LT1210 for control and amplified the signal input. This is the figure of the circuit.


Bridging can be used to increase the output power transferred to a transformer. Differential operation also promotes the cancellation of even-order distortion. In the figure is shown a differential application using an LT1207 as a bridge driver for HDSL. [Schematic source: Linear Technology Corporation, Inc].

High Current MOSFET Toggle Switch Circuit

This is a circuit design for high current toggle switch. This circuit was adapted from the "Toggle Switch Debounced Pushbutton" by John Lundgren. It is useful where the load needs to be switched on from one location and switched off from another. Any number of momentary (N/O) switches or push buttons can be connected in parallel. This circuit is work with based on transistor as controller the circuit. This is the figure of the circuit.


The combination (10K, 10uF and diode) on the left side of the schematic insures the circuit powers up with the load turned off and the NPN transistor conducting. These components can be omitted if the initial power-on condition is not an issue. When a switch is closed, the 1uF cap voltage is connected to the junction of the 220 ohm and 33K resistors causing the circuit to change state. When the switch is opened, the cap charges or discharge to the new level through the 1M resistor, and the circuit is ready to toggle again in about 1 second. It takes a little time for the cap to move to the new level, either +V or ground. The (0.1uF) capacitor at the transistor base was added to press noise that might cause false triggering if the switches are located far away from the circuit. The circuit was tested using a 12 volt, 25 watt automotive lamp, and IRFZ44. Other MOSFETs can probably be used. [Schematic diagram source: Bill Bawden]

Pulse Generator And Signal Tracer Circuit Using Transistor

This is a simple circuit that can used to generate narrow pulses at about 700-800Hz frequency. The pulses, containing harmonics up to the MHz region, can be injected into audio or radio-frequency stages of amplifiers, receivers and the like for testing purposes. This circuit is built by two transistor. This is the figure of the circuit.


Operation of the circuit is Q1 & Q2 form a complementary unstable multi vibrator, whose operating frequency is set mainly by R3, C2 & C3 values. Output pulses are taken at Q2 Collector and applied to the probe by means of decoupling capacitor C1. D1 provides a symmetrical shape for the output waveform. If an earclip or headphone jack is plugged into J1, the connection from Q2 Collector and C1 - C2 is broken by the switch incorporated into J1: in this case the circuit becomes a two-stage amplifier. If you intend to use the circuit to test valve operated devices C1 must be a 630V type. Working with low voltage supply transistor devices the voltage of C1 can be lowered to 63 or 100V. A crystal (high impedance) earpiece is a good solution, provided you substitute J1 with a mono switched jack socket.

In below is the listing component that can be used to built up the circuit.
R1 1M 1/4W Resistor
R2, R4 2K7 1/4W Resistors
R3 150K 1/4W Resistor
C1 2n2/630V
C2, C3 4n7/ 63V
D1 1N4148 75V 150mA Diode
Q1 BC547 45V 100mA NPN Transistor
Q2 BC557 45V 100mA PNP Transistor
SW1 SPST miniature Slider Switch (See Notes)
J1 Stereo switched 3mm. Jack socket (See Notes)
Probe Metal Probe 3 to 5 cm. long
Clip Miniature Crocodile Clip
B1 1.5V Battery (AA or AAA cell etc).

Stereo Line Driver Circuit Using Transistor

This is the schematic diagram of a low cost stereo line driver. The circuit is based only two transistors and few passive components. This is the figure of the circuit.


The description work of the circuit is each BC 109C transistor is wired as an emitter follower for driving each channel. The voltage gain of the emitter follower is unity, but it has a high current gain and low output impedance, ideal for driving long cables. The output impedance is around 16 Ohms at 1KHz.Since voltage gain is unity power amplifiers must be used at the listening end in order to drive loud speakers. The circuit can be powered from a 12V battery or 12V DC power supply. A power amplifier is needed at the listening end because the emitter follower has only unity voltage gain. The inputs and outputs must be connected with respect to ground as shown in circuit.

DoZ Preamp as a Driver Power Follower

To get the voltage gain needed for a normal installation, the DoZ preamp can be used. Everyone who has built this circuit has commented on the exceptional sound quality, and it is ideally suited to this application.

Figure shows the modified version of the preamp, the output of which would be connected directly to R1 in the circuit. The quiescent output voltage is now set by VR1 in the preamp, and the voltage at the source of T1 should be set to 19.8V as shown in Figure 1 by means of VR1 - the voltage at the gate (preamp output) should be 4V higher, i.e. 23.8V. The DoZ preamp board is stereo, and can drive a pair of the power followers with ease. Q2 and Q3 should be fitted with small "flag" heat sinks to allow them to dissipate the increased power caused by the higher operating voltage.

As shown, the gain is 3.2, so it will require nearly 4V RMS input for full power. To change the gain, I suggest that R4 be changed to 3k3 to obtain a gain of 7.7 (17.7dB), which will give an input sensitivity of about 1.5V for maximum output. C3 will also need to be changed, and a value of 100uF will be more than adequate. I do not recommend that R4 be reduced to less than 2k7, which will give a gain of 9.15 (19.2dB). To maintain good low frequency response, C3 will need to be about 100uF, although even with 25uF, the low frequency response is maintained to 2Hz. Ideally, the input network should define the low frequency limit, so the higher value is recommended if R4 is reduced.

Unless a preamp is used in front of the amp, a pot will be needed at the input for gain control. 10k is fine here, and will not cause excessive loading on the source.

DC Motor Driver

These days robot activator system of course has applied muscle cable ( muscle wire) but mostly a lot still remain to applies motor as prime mover to remember torsion from muscle cable still too low. DC motor is motor having speed of high rotary. With addition gearbox, hence this motor applicable to move parts of robot requiring big torsion like at part to implement the robot.

Part of this is part executing command from CPU>Central Processing Unit Board activity what would which must be done at motors DC at part of mechanic of the application of this robot.

At part of port that is connect with good motor of motor 1 and motor 2 there is output of VCC and GND which is pole source of tension 5 Volt and 0 Volt for operation of DC motor using rotary encoder. Pin Encoder is modulation has happened result from rotation of DC motor using rotary encoder. Function of rotary encoder is to count rotation which already happened at motor. Modulation from rotary encoder is entering through foot/feet Encoder will be continued towards to CPU>Central Processing Unit Board through foot/feet Right Encoder and or Left Encoder at Port CPU>Central Processing Unit.

DC Driver also has breakdown voltage protector protecting electronic system from back tension as result of rotation of DC motor. Also there is circuit gate avoiding condition of ON from all the transistors so that system protected from condition of linking is brief often happened at system half bridge.

DC Driver is part of controller module or can be analogy as executor from command received by Robot CPU. In DC Driver there is circuit Half Bridge equipment with by preventative circuit gate the happening of linking brief.

Half Bridge is a network applied to control a DC motor so that hinged be unidirectional and or anti clockwise. Activity principle Half Bridge is arranges current stream at DC motor. If current stream is returned by hence DC motor will rotate towards on the contrary. Simple circuit Half Bridge can be built by two switches SPDT like the one seen at picture following.

Now seen that switches S1 connects pole on the top motor to positive pole source of battery, and S2 connects pole in motor underside to negativity pole source of power battery so that current at motor flows from the top of downwards. To change rotation of motor by making a change direction of current stream is done with moving position of S1 and at the same S2 so that motor top connected at negativity pole battery and undercarriage to positive pole.

Picture 3 shows network Half Bridge which more complex and is ½ part of Delta DC Driver. Switches S2 is replaced with transistor circuit type NPN that is transistor TIP41 and C9014 while switches S1 is replaced with transistor network type PNP that is TIP42 and C9012. Position of switches S1 is represented with position of which p-n p transistor is active while position of switches S2 is represented with position of which active n p-n transistor.

If active left p-n p transistor, hence right n p-n transistor also active while PNP xenon right must be active and left NPN of active xenon. Current will flow from positive resource to pin 3 JP4 which connecting at motor pole and continued to be finite of foot/feet 4 JP4 to negative resource or ground. On the contrary at the time of active right p-n p transistor, hence left n p-n transistor also active while left PNP xenon must be active and right NPN also active xenon. Current will flow from resource to pin 4 JP4 and always towards to negative resource passed pin3.