Schematic & Wiring Diagram

The circuit diagram is given here is a motor controller driver using the Motorola MC3479. The MC3479 is designed specifically for driving a stepper motor phase 2 in bipolar mode and is available in standard DIP and surface mount IC packages.The is compatible with TTL and CMOS and has selectable HI / LOW output impedance .

The output can deliver up to 350 mA each of the two coils of a stepper motor 2 phases. The change of output state occurs in the low to high transition of the input clock pulse. The new output will depend on the exit of age and state of the digital inputs. The output L1 to L4 are the results of high currents, which when connected to a stepper motor a two-phase full-bridge two formations.

Resistors R1 and Rb, Zener diode D1 and IC2 MC14049UB are additional components that are used in the circuit. R1 is an uprising and resistance Rb is used to set the maximum output sink. Zener diode D1 provides back emf protection.

With MAX2606 you can make a Mini mono FM transmitter. It is built with MAX2606 and covers at least 20 meters with 1.5 m length of copper wire antenna. You can use this transmitter as an oscillator, but change the 1000pF capacitor of the antenna with 15pF.

MAX2606 transmitter output power is-10dBm, which means something around 100uW (micro-watts) = 0.0001. Of course this is very low, so it is recommended the use of auxiliary power amplifier, if you want to build a more powerful transmitter based on MAX2606. You can find a power amplifier in a few fm electroschematics.com so please use the search box.

This circuit is designed to indicate the power level output of any audio amplifier. It's simple, portable, and displays three power levels can be adjusted to any desired value. For a standard power amplifier hi-fi stereo, the output values ​​suggested are:

• D5 illuminates at 2W
• D4 illuminates at 12.5W
• D3 illuminates at 24.5W

The above values ​​were selected for easy setup, but other options are possible. IC1A is the input buffer, feeding 3 voltage comparators and LEDs drivers by means of a variable DC voltage obtained by R5 and C4 smoothing action. In order to achieve stability of adjustment, the supply of IC1 and trimmers R6 and R7 is reduced and is subject to 5.1V by Zener diode D1.

The objective of this project was to design a small portable mixer supplied by a 9V PP3 battery, keeping performance quality. The mixer is formed assembling three main modules that can vary in number and / or willingness to adapt to the needs of all.

The three modules are:

Amplifier Input Module: a low-noise circuit equipped with a variable voltage gain (10 - 100) pre-set, primarily intended as input to high-quality microphone is also suitable for line level input on .

Tone Control Module: One of three bands (Low, Mid, Treble) tone control circuit provides unity gain when the controls are set flat frequency response. Can be inserted after one or more modules of the amplifier and / or after the main mixer amplifiers.

Main Module mixer amplifier, a music circuit incorporating two virtual mixing earth and shows the connection of a Master Fader and Pan-Pot.

This Audio Amplifier design is based on the audio amplifier 18 watts, and was developed primarily to meet the requests of correspondents unable to locate the chip TLE2141C. It uses the NE5532 Dual IC wide, but obviously, its power output will be written in the 9.5 - 11.5W range, as the supply rails can not exceed ± 18V.

As amplifiers of this type are often used to drive small loudspeaker cabinets, the bass frequency range is rather sacrificed. Therefore, a Bass Boost control was inserted in the amplifier feedback loop, in order to overcome this problem, without loss of quality. The low elevation curve can reach a maximum of 16.4 dB @ 50Hz. In any case, even when the bass control is turned fully counterclockwise, the amplifier's frequency response curve shows a gentle rise: 0.8 dB at 400 Hz, 4.7 dB at 100 Hz and 6 dB at 50 Hz (referred to 1 kHz).

Those who want to listen privately to your music program should add this headphone amplifier in the chain of modular preamp. The circuit is kept as simple as possible consistent with high quality performance. This was achieved by using two NE5532 operational amplifiers on a circuit where IC1B is the "master" amplifier in the cable joint inversion of configuration is not already used in the amplifier's control center line. IC1A is the "slave" of the amplifier and is configured as a unity gain buffer: parallel amplifiers to increase the output current capacity of the circuit.
Two headphone outputs are provided by J3 and J4.

The AC gain of the amplifier was deliberately kept low because this module is intended to be connected after the Control Center module, which provides sufficient gain to drive the power amplifier. If you intend to use the headphone amplifier as a standalone device, an AC higher gain may be necessary to cope with a CD player or tuner output. This is achieved by reducing the value of R1 to 1K5. Thus AC gain of 9 is obtained, more than enough for the purpose.

Unlike the two ICs 15V positive and negative regulator used in other modules of this preamp, two devices were used instead of 9V. This is because the NE5532 automatically limits the output voltage at very low loads as 32 Ohm so that the output amplitude of the amplified signal remains the same, whether the circuit is powered by ± 15V to ± 9V. The choice of a source of ± 9 V allows lower power dissipation and better performance of the amplifier near the cutoff point.

The input jack of this amplifier must be connected to the output module main control center. As this output is usually reserved for driving the power amplifier, a second connection (J2) connected in parallel to J1 is provided for this purpose.

As with the other modules in this series, each electronic card can be fitted in a standard: Hammond extruded aluminum cases are well suited to accommodate the tables in this preamp. In particular, instances of size 16 x 10.3 x 5.3 cm or 22 x 10.3 x 5.3 cm look very good when stacked. See below an example of the possible arrangement of the front and back of this module.

This simple circuit helps you sniff out RF radiation from your transmitter, improper joints, a broken wire or poor equipment with RF shielding. The tester is designed for the radio band amateur 2 meter (144-146 MHz in Europe). The instrument has a reading of 4-step LED and an audible alarm for high voltage radiation. The RF signal is received by an antenna and made to resonate by C1-L1. After rectification by the diode D1, the signal is fed to a two transistor Darlington amplifier HighGain, T2-T3. Assuming a 10-inch telescoping antenna using the RF level scale established for the LEDs is as follows:

When all the LEDs light, the (optional) UM66 sound / melody generator chip (IC1) also operates and provides an audible alarm. By changing the zener diode values ​​of D2, D4, D6 and D8, the step size and duration of the instrument may change as needed. To operate in other bands of ham or PMR, simply change the network-L1 C1 resonance.

For example, a transceiver 5 watt handheld equipped with a telescoping half-wave antenna (G = 3.5 dBd), there is an ERP (Effective Radiated Power) of just 10 watts and an emf of more than 8 volts near the head. Inductor L1 consists of 2.5 turns of 20 SWG (approximately 1 mm in diameter) enameled copper wire. The inner diameter is approximately 7 mm and no core is used.

Trimmer capacitor C1 associates is adjusted for the greatest number of LEDs to light at a relatively low fieldstrength position for a 2 m transceiver 145 MHz transmission. The tester is powered by a 9 V battery and consumes about 15 mA when all LEDs are on. Must be enclosed in a metal box.

TDA1514 is a hi fi audio amplifier may output of 50W of sound. The power supply is 10V and 30V. Can be used as an amplifier at home.

The integrated circuit TDA1514 power amplifier is a high fidelity for use as a basic component in applications of radio, television and other audio. The TDA 1514 is fully protected circuit, also has a mute function that can be arranged for a period after the ignition delay time set by external components. The device is designed to power symmetric, but asymmetric source can also be used. For stereo amplifier configuration uses two identical circuits.

The circuit shown is a stereo FM PLL demodulator designed based on the AN7415. C1 is the input coupling capacitor to block any DC voltage present on the multiplexed input signal. LED D1 is an LED and R1 is the current limiting resistor. C4 and C5 are DC decoupling capacitors to the output channels left and right. C2 and C3 are bypass capacitors for noise output channels left and right. POT R2 can be used to adjust the separation between channels.

The resistor R5 and capacitors C7 and C8 form a network of low-pass filter for the internal DC amplifier circuit (see block diagram AN7415). C10 is a filter capacitor for the internal amplifier circuit Schmitt trigger IC. C9 is a filter capacitor for the circuit wave surge inside the AN7415. Resistor R3, R4 and capacitor C6 POT set the time constant of internal VCO circuit. Therefore POT R4 can be used to adjust the frequency of the VCO. A control signal 19KHz frequency is available in 12 pin IC. The switch S1 can be used to activate and deactivate the forced mono.

Here is the circuit diagram of a simple subwoofer filter that can be operated from a 12V DC supply. This circuit is very useful in car subwoofer applications. The circuit is simply a low pass filter whose pass frequency can be adjusted between 60 and 160 Hz.

The circuit is designed around the dual TL072 IC BIFET. Outside the two operational amplifiers in the chip, IC1A is connected as a buffer. The audio inputs left and right after the mixture is fed to the input of the switch S1 IC1A with bipolar. Switch S1 is the phase control switch that can be used to make the subwoofer in phase with the other speakers. When S1 is in position 2, 180 degrees of phase change induced.POT R7 can be used to control the level. IC1B a low pass filter whose pass frequency can be controlled by adjusting the dual band POT R13.

This FanTemperature Controller circuit design technique to adopt a more ancient as its objective is to vary the fan speed in relation to temperature with a fraction of counting and avoid using special-purpose integrated circuits, often difficult to obtain.

R3-R1-R4 and P1 are connected as a Wheatstone bridge in which R3-R4 generates a fixed two-thirds of the supply of "reference" voltage, P1-R1 generates a temperature-sensitive "variable" power and Q1 is used as a balanced bridge detector.

P1 is adjusted so that the "reference" stress "variable" is equal to a temperature just below the critical value necessary, and under the base of Q1 and the condition of the issuer are located in the same tensions and Q1 cut. When the temperature rises above this R1 "balance" the value of P1-R1 voltage falls below the "reference" value, so that Q1 is polarized, pulse charging C1.

This is because the circuit is supplied by a 100 Hz half-wave voltage from the mains supply by means of the D3-D6 diode bridge without filter capacitors and fixed to 18V by Zener diode D1 and R9. Therefore the supply of 18 volt DC circuit is not true, but it has a trapezoidal shape instead. C1 provides a variable lag phase pulse train related to temperature and synchronized with the mains "zero voltage" point of each half cycle, resulting in minimal change RFI SCR. Q2 and Q3 form a firing device, which generates a short pulse suitable for driving the SCR.

This FM wireless microphone is easy to build and has a useful range of transmission (over 300 meters outdoors). Despite its small number of components and an operating voltage of 3V to easily penetrate over three floors of an apartment building. You can tune anywhere on the FM band (87-108MHz) and its transmissions can be picked up at any point of view of the FM receiver.

The coil (L1) should be approximately 3 mm in diameter, 5 turns 0.61 mm copper wire. You can vary the Tx frequency by simply adjusting the distance between the coils. The antenna should be a half wavelength or quarter-time (100 MHz, 150 cm or 75 cm).

Parts list:

• T1,T2,T3: 2N2222 transistor
• R1: 10k 5%
• R2: 33k lin.
• R3: 12k 5%
• R4: 5.6k 5%
• R5: 2.2k 5%
• R6,R8: 47k 5%
• R7: 470 ohms 5%
• R9: 180 ohms 5%
• C1,C2: 47nF
• C3: 1nF
• C4: 33pF
• C5: 5.6pF
• C6: 8.2pF
• C7: 10nf
• L1: 3mm in diameter with 5 turns 0.61 mm copper wire
• K1: SPDT toggle switch
• Other parts: 2 AA battery holder, Electret microphone, antenna wire

Here is a 7 segment counter circuit based on IC 74LS90 TTL.This can be used in conjunction with several circuits where a counter to show the progress adds a little more attractive. This circuit accepts any TTL compatible logic signal, and can be extended easily.

This a stereo tone control circuit built using LM1036 IC. This control circuit bass / treble tone level, volume and balance between the right channel and left channel (Input 1 and 2). You can use this circuit for stereo applications such as car radio, television and audio systems, MP3 player, DVD player, ipod and more. An additional control input allows loudness compensation to be made simply. The circuit must be working with a supply voltage of 9V to 15V DC.

Each tone response is defined by a single capacitor chosen to give the desired characteristic. By changing the values ​​of capacitors connected to the tone control unit, you can control bass and treble levels. pin 3 and pin 18 of IC are for acute and pin 6 to pin 15 for bass.