Single Chip Theremin Circuit

 This schematic diagram show a single chip Theremin circuit.  Theremin is an electronic music instrument which sense hand movement to control the tones/frequency. This Theremin circuit uses two separate Colpitts LC oscillators to produce a beat frequency. The frequencies of  two Colpitts LC oscillators are mixed and then rectified.

RJ45 Port Pinout Circuit

 

RJ45 connector is used for connecting Ethernet port on computer and in Internet system. There are two configuration: straight and cross. This is the figure of the RJ45 connector;

Tremolo Effect Circuit for Electric Guitar

 

Tremolo circuit is a kind of sound effect. We can see this type of effect is applied  in guitar effect pedals.  Tremolo effect is produced if we modulate the amplitude of an audio signal. The shape of modulating signal can vary from square wave, sawtooth wave, or sine wave. When we use a square wave, then the effect produce a knocking-like sound which might be perceived like a percussive instrument.

Compact 3W BTL Audio Power Amplifier Schematic TDA7056

 Bridge-tied-load (BTL) configuration in an amplifier is basically a H-network  with the loud-speaker as the “bridge” between two active valve or switcher. This configuration allow a full alternating current signal to be produced at the load (loudspeaker) without a transformer or a symmetric power supply. Here are some benefits of BTL configuration:

Power Supply Circuit for Arduino

 This is the schematic diagram powers our Arduinos. For this, we can use either DC power supply or USB connection as a source. To trace how the circuit works, let us start with the 5V linear voltage regulator NCP1117ST50T3G. This regulator has a pretty straightforward function. It takes voltage input up to 20V and converts it to 5V. The Vin of this regulator is connected to the DC power supply via the M7 diode. This diode provides reverse polarity protection, which means current can only flow from the power supply to the regulator and not the other way around. This the figure of the circuit.

 

RLC Resonance Circuit

 At low frequencies, L1 looks like a short circuit, and C1 looks like an open circuit, so V(in) and V(out) are closely linked by R1. At high frequencies, L1 looks like an open circuit and C1 looks like a short circuit, so V(out) approaches zero. But in the middle range of frequencies, something interesting happens. In fact, for a narrow range of frequencies around 1MHz, this circuit actually produces a tremendous amount of voltage amplification!

 

Audible Logic Probe/Indicator Circuit

Logic indicator circuit / logic probe is used to identify logic level at any point of logic circuitry. The indicator can be visual (using LED, LCD, of 7 Segments) or auditory (using beeper or speaker). This circuit has a audible indicator, with the help of  a loudspeaker to produce indication tone.  Using the opamp,U1, as schmitt trigger, the Audio oscillator Q3-Q1-Q2 is isolated from TTL. Beside that, the op amp also acts as high input impedance inverter. The R8-R9 is used to set reference level at +16.6V which is a midway between low and high logic level. The Q3-Q2 will generate tone that indicate a high logic when the probe voltage is above +1.6V. If the probe voltage is below +1.6V then the  OP-amp output will saturate the Q1 and disables Q3-Q2 to cut off tone. Here is the schematic diagram of the circuit:

LT1016 – LS74121 Voltage Controlled Pulse Width Generator/ Monostable Multivibrator

Here’s the Mono-stable multivibrator circuit generates a fixed pulse width when receiving a trigger signal on its input. The pulse width of the output is fixed regardless of the input pulse duration/width. In practical application, the width of the output pulse is determined by choosing the right components values for certain application. In today’s digital electronics, mono-stable function can be easily implemented using micro controller. In many practical they’re more than enough, but many experimental works sometime need very specific function with high speed performance while maintaining its flexibility. This is the figure of the circuit diagram.

High Voltage Conductivity Tester Schematic

Here’s a design circuit a conductivity tester, but differs in that it uses large test voltage (140V). It is suitable wherever you can't use common testers, like multimeters and similar. High voltage conductivity tester is good for testing HV diodes, multipliers, neon lamps, LED and LED modules, capacitors, insulation, Zener diodes, transils, search the cold end of IHVT, DST secondary and testing its diodes. Together with parallel voltmeter it is usable to measure HV diodes voltage drop, Zener voltage of zener diodes, voltage drops of LEDs and LED modules, transils and operating voltage of neon glow lamps. Along with serial mili / microammeter it allows measurement of very high resistance and leakage currents. (Multimeters have a built-in diode tester, which measures the diode voltage drop, but the maximum voltage is only 2V, which for these purposes very low.) Here is the figure of the schematic.

 

Active Load Circuit for Power Supply Tester

 Here’s a design circuit for active load that can be used in Power supply with base in 5V 2A. This circuit is based on a scrap of perf-board using a medium power NPN transistor. I used a TIP41B because I had some, but those are not recommended for new designs. Almost any decent NPN power transistor or N-channel power FET will work in this application. This is the figure of the circuit.

 

Loudspeaker Peak Indicator Circuit Schematic

When a Modern loudspeakers boxes condition are relatively insensitive to overdriving signals, however it is still important to limit the power driving it to avoid clipping of the audio signal. A broken sound from an overdriven loudspeaker is not only annoying to the the ears but also the loudspeaker itself can be damaged by the continous uncontrolled signal peaks. This is the figure of the schematic;

Linear Optocoupler Circuit Schematic

This is a design for linear optocoupler is built with MOC5010 and can be used to isolate a circuit from main grid, audio interface, in medical electronics and many other applications. Because of its high isolation resistance (10¹¹ Ω), MOC5010 is used in applications where a circuit is powered directly from main power. With a bandwidth from 5 Hz to 100 kHz you have no reason to complain about audio signal response. This is the figure of the circuit.

Brake Lights Schematic Circuit

This is a for a cars about  the break lamps. They have a subdivision of the green circuit with its own in-line 35 amp fuse supplied by the white/brown (ignition relay) circuit feeding things like heated rear window, indicators, heater fan and tach, which leaves the original green circuit fuse (2nd one up in the four-way fuse block) feeding things like reverse lights, stop lights, washers, wipers, and circuits associated with the seat belt warning lamp and time delay buzzer. This is the figure of the diagram circuit.

Thermostat Temperature Sensor Schematic

This is a sensor that design type electro-mechanical temperature sensor or switch, that basically consists of two different metals such as nickel, copper, tungsten or aluminium etc, that are bonded together to form a Bi-metallic strip. The thermostat can be used itself as an electrical switch or as a mechanical way of operating an electrical switch in thermostatic controls and are used extensively to control hot water heating elements in boilers, furnaces, hot water storage tanks as well as in vehicle radiator cooling systems. This is a figure schematic for the sensor.

TLP310xA - High Current Photo Relays

This is relay that produce by Toshiba corporation. This is new high current photo relays that have 3 types. They are called TLP3106A, TLP3107A and TLP3109A. These devices have an off-state output terminal voltage ranging from 30-100V and a steady on-state current of 3.0 to 4.5A in a small 2.54SOP6 package for factory automation and industrial applications. This is the figure of the relays.

Half Wave Rectifier Schematic

This is a design of a half-wave rectifier  that is uses only half of the input cycle to produce an output. The induced voltage across L2 (the transformer secondary) that will be shown on the schematic diagram. The dots (polarity marks) on the transformer indicate points of the same polarity. During the portion of the input cycle that is going positive (solid line), CR1, the PN junction diode, will be forward-biased and current will flow through the circuit. L2, acting as the source voltage, will have current flowing from the top to the bottom. This current then flows up through RL causing a voltage drop across RL equal to the value of current flowing times the value of RL. This voltage drop will be positive at the top of RL, with respect to its other side; and the output will therefore be a positive voltage with respect to ground. This is the figure of the schematic.

Low Power 12V Transformerless Power Supply Circuit

 

Here is design powered directly from the mains with the aid of a series capacitor (C1). The disadvantage of this approach is that usually only one half cycle of the mains wave-form can be used to produce a DC voltage. An obvious solution is to use a bridge rectifier to perform full-wave rectification, which increases the amount of current that can be supplied and allows the filter capacitor to be smaller. The accompanying circuit in fact does this, but in a clever manner that uses fewer components. Here we take advantage of the fact that a Zener diode is also a normal diode that conducts current in the forward direction. During one half wave, the current flows via D1 through the load and back via D4, while during the other half wave it flows via D3 and D2. Bear in mind that with this circuit (and with the bridge rectifier version), the zero voltage reference of the DC voltage is not directly connected to the neutral line of the 230-V circuit. This is the figure of the circuit;

 

Time Manipulator Circuit

This is a design circuit for a type guitar effect. This circuit can be used as delay, reverb or echo because this circuit is use time manipulator. It uses two PT2399 delay integrated circuits to archive up to 600ms delay. Also, with the help of 4 analog switches, the internal configuration of the pedal can change: placing the PT2399 delay chips in series or parallel and adding extra features. This is the figure of the circuit;

Spring Reverb Schematic Circuit

This is design for guitar reverb. Spring reverb units are most commonly used in guitar amps, having been replaced by digital effects in most other areas.  The circuitry will always be somewhat experimental, and may change quite dramatically depending on the type of spring reverb unit you can actually get your hands on.  The PCB is designed (available soon) to accommodate most reverb tanks, with the optimum being those with a low impedance drive coil. This is the figure of the complete schematic diagram of the Spring Reverb circuit.

Since the P113 headphone amp is very easily modified for constant current drive, this used to be recommended because it works very well.  However, wiring the two halves of the P113 board differently is somewhat clumsy, and while it works well it’s not ideal.  The circuit shown here uses the same drive system, and has everything else that's needed for a complete reverb system.  The circuit shown in Figure 2 is the latest incarnation of the reverb circuit.  Unlike the others that are somewhat 'piecemeal', it's a complete reverb sub-system. 

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.