Transistor Ignition circuit Schematic with explanation

This transistor ignition circuit give your car to have better starting and smoother running, particularly at very high and very low RPM. Lower fuel consumption, less pollution, lower servicing costs. Drive economically, drive electronically. Only for petrol/gasoline engines. This circuit will reduce breaker point wear and provide cleaner spark.

Circuit diagram:

Wiring diagram with the vehicles:

Notes:
This circuit used for cars with negative ground 12V negative ground system, maximum ignition current of 4A and maximum switching speed 500KHz. Motorcycles, mowers, boats, etc can also use this circuit.

For 6V Negative ground system, change the following resistors:

• R1, R2: 150 ohm / 1W
• R3 : 68 ohm / 1/4W
• R4 : 100 ohm / 1/4W
• R5, R6, R7: 68 ohm / 1W

The kit of Electronic Transistor Ignition is available at electronickits.com, sell at $25.95.
Download the manual Transistor Ignition kit HERE

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With Bass-Boost 10W Audio Amplifier High Quality, very simple design, No preamplifier required

High Quality, very simple design, No preamplifier required

This design is based on the 18 Watt Audio Amplifier, and was developed mainly to satisfy the requests of correspondents unable to locate the TLE2141C chip. It uses the widespread NE5532 Dual IC but, obviously, its power output will be comprised in the 9.5 - 11.5W range, as the supply rails cannot exceed ±18V. As amplifiers of this kind are frequently used to drive small loudspeaker cabinets, the bass frequency range is rather sacrificed. Therefore a bass-boost control was inserted in the feedback loop of the amplifier, in order to overcome this problem without quality losses. The bass lift curve can reach a maximum of +16.4dB @ 50Hz. In any case, even when the bass control is rotated fully counterclockwise, the amplifier frequency response shows a gentle raising curve: +0.8dB @ 400Hz, +4.7dB @ 100Hz and +6dB @ 50Hz (referred to 1KHz).

Amplifier with Bass-Boost:

10W Bass Boost Amplifier Circuit Diagram

Parts:

P1_________________22K Log.Potentiometer (Dual-gang for stereo)
P2________________100K Log.Potentiometer (Dual-gang for stereo)
R1________________820R 1/4W Resistor
R2,R4,R8____________4K7 1/4W Resistors
R3________________500R 1/2W Trimmer Cermet
R5_________________82K 1/4W Resistor
R6,R7______________47K 1/4W Resistors
R9_________________10R 1/2W Resistor
R10__________________R22 4W Resistor (wirewound)
C1,C8_____________470nF 63V Polyester Capacitor
C2,C5_____________100µF 25V Electrolytic Capacitors
C3,C4_____________470µF 25V Electrolytic Capacitors
C6_________________47pF 63V Ceramic or Polystyrene Capacitor
C7_________________10nF 63V Polyester Capacitor
C9________________100nF 63V Polyester Capacitor
D1______________1N4148 75V 150mA Diode
IC1_____________NE5532 Low noise Dual Op-amp
Q1_______________BC547B 45V 100mA NPN Transistor
Q2_______________BC557B 45V 100mA PNP Transistor
Q3_______________TIP42A 60V 6A PNP Transistor
Q4_______________TIP41A 60V 6A NPN Transistor
J1__________________RCA audio input socket

Power Supply :

Power Supply Circuit Diagram

Power supply parts:

R11_________________1K5 1/4W Resistor
C10,C11__________4700µF 25V Electrolytic Capacitors
D2________________100V 4A Diode bridge
D3________________5mm. Red LED
T1________________220V Primary, 12 + 12V Secondary 24-30VA Mains transformer
PL1_______________Male Mains plug
SW1_______________SPST Mains switch

Notes:

• Can be directly connected to CD players, tuners and tape recorders.
• Schematic shows left channel only, but C3, C4, IC1 and the power supply are common to both channels.
• Numbers in parentheses show IC1 right channel pin connections.
• A log type for P2 will ensure a more linear regulation of bass-boost.
• Do not exceed 18 + 18V supply.
• Q3 and Q4 must be mounted on heatsink.
• D1 must be in thermal contact with Q1.
• Quiescent current (best measured with an Avo-meter in series with Q3 Emitter) is not critical.
• Set the volume control to the minimum and R3 to its minimum resistance.
• Power-on the circuit and adjust R3 to read a current drawing of about 20 to 25mA.
• Wait about 15 minutes, watch if the current is varying and readjust if necessary.
• A correct grounding is very important to eliminate hum and ground loops. Connect to the same point the ground sides of J1, P1, C2, C3 &C4. Connect C9 to the output ground.
• Then connect separately the input and output grounds to the power supply ground.

Technical data:
Output power:
10 Watt RMS into 8 Ohm (1KHz sinewave)
Sensitivity:
115 to 180mV input for 10W output (depending on P2 control position)
Frequency response:
See Comments above
Total harmonic distortion @ 1KHz:
0.1W 0.009% 1W 0.004% 10W 0.005%
Total harmonic distortion @ 100Hz:
0.1W 0.009% 1W 0.007% 10W 0.012%
Total harmonic distortion @ 10KHz:
0.1W 0.056% 1W 0.01% 10W 0.018%
Total harmonic distortion @ 100Hz and full boost:
1W 0.015% 10W 0.03%
Max. bass-boost referred to 1KHz:
400Hz = +5dB; 200Hz = +7.3dB; 100Hz = +12dB; 50Hz = +16.4dB; 30Hz = +13.3dB
Unconditionally stable on capacitive loads

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Playback Amplifier For Cassette Deck circuit schematic with explanation

For some time now, there have been a number of tape cassette decks available at low prices from mail order businesses and electronics retailers. Such decks do not contain any electronics, of course. It is not easy to build a recording amplifier and the fairly complex magnetic biasing circuits, but a playback amplifier is not too difficult as the present one shows. The stereo circuits in the diagram, in conjunction with a suitable deck, form a good-quality cassette player. The distortion and frequency range (up to 23 kHz) are up to good standards. Moreover, the circuit can be built on a small board for incorporation with the deck in a suitable enclosure. Both terminals of coupling capacitor C1 are at ground potential when the amplifier is switched on.

Circuit diagram:

Cassette Deck Playback Amplifier Circuit Diagram

Because of the symmetrical ±12 V supply lines, the capacitor will not be charged. If a single supply is used, the initial surge when the capacitor is being charged causes a loud click in the loudspeaker and, worse, magnetizes the tape. The playback head provides an audio signal at a level of 200–500 mV. The two amplifiers raise this to line level, not linearly, but in accordance with the RIAA equalization characteristic for tape recorders. Broadly speaking, this characteristic divides the frequency range into three bands:

• Up to 50 Hz, corresponding to a time constant of 3.18 ms, the signal is highly and linearly amplified.
• Between 50 Hz and 1.326 kHz, corresponding to a time constant of 120 µs, for normal tape, or 2.274 kHz, corresponding to a time constant of 70 µs, for chromium dioxide tape, the signal is amplified at a steadily decreasing rate.
• Above 1.326 kHz or 2.274 kHz, as the case may be, the signal is slightly and linearly amplified. This characteristic is determined entirely by A1 (A1’). To make the amplifier suitable for use with chromium dioxide tape, add a double-pole switch (for stereo) to connect a 2.2 kΩ resistor in parallel with R3 (R3’). The output of A1 (A1’) is applied to a passive high-pass rumble filter, C3-R5 (C3’-R5’) with a very low cut-off frequency of 7 Hz. The components of this filter have exactly the same value as the input filter, C1-R1 (C1’-R1’). The second stage, A2 (A2’) amplifies the signal ´100, that is, to line level (1V r.m.s.).

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Condenser Mic Audio Amplifier circuit Schematic with explanation

The compact, low-cost condenser mic audio amplifier described here provides good-quality audio of 0.5 watts at 4.5 volts. It can be used as part of intercoms, walkie-talkies, low-power transmitters, and packet radio receivers. Transistors T1 and T2 form the mic preamplifier. Resistor R1 provides the necessary bias for the condenser mic while preset VR1 functions as gain control for varying its gain. In order to increase the audio power, the low-level audio output from the preamplifier stage is coupled via coupling capacitor C7 to the audio power amplifier built around BEL1895 IC.

Circuit diagram:

Condenser Mic Audio Amplifier Circuit Diagram

BEL1895 is a monolithic audio power amplifier IC designed specifically for sensitive AM radio applications that delivers 1 watt into 4 ohms at 6V power supply voltage. It exhibits low distortion and noise and operates over 3V-9V supply voltage, which makes it ideal for battery operation. A turn-on pop reduction circuit prevents thud when the power supply is switched on. Coupling capacitor C7 determines low-frequency response of the amplifier. Capacitor C9 acts as the ripple-rejection filter.

Capacitor C13 couples the output available at pin 1 to the loudspeaker. R15-C13 combination acts as the damping circuit for output oscillations. Capacitor C12 provides the boot strapping function. This circuit is suitable for low-power HAM radio transmitters to supply the necessary audio power for modulation. With simple modifications it can also be used in intercom circuits.
Author: D. Prabakaran - Copyright: Electronics For You Mag

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latest Electro Harmonix Graphic Equalizer circuit schematic with explanation

This is the diagram od electro-harmonix graphic equalizer. You can specify the number of channels according to your needs. You just need to parallel the components: C1, C2, R1, an om-amp, Potensiometer and a 470 ohm resistor. The frequency to be boost decided by C1, C2 and R1. See the diagram for the C1, C2 and R1 combination versus the frequency.

For the op-amp, you can use op-amp IC TRX6221, NE5532 or LM833. Use regulated power supply and high quality components to obtain the quality audio output.

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Gibson RD Artist Guitar circuit schematic with explanation

The following diagram is the schematic of Gibson RD Artist bass guitar

Circuit Notes:

1. Both compression and expansion effects are determined by the lead pickup output only.
2. I and O in the design diagram refer to inner and outer connections for the specific plug / jack.
3. P and J in the design diagram refer to plugs and jacks respectively.
4. The two green wires connecting to the P1- (5,6) are signal grounds. P1-8 being used for plug priority sensing.

Gibson RD Artist guitar schematic diagram designed by Fabian P Hartery

Download the schematic in PDF file:
» Download Link

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Car Headlight Alarm circuit Schematic with explanation

This car headlight alarm circuit can be set for one or two functions:
First, to indicate that the head lights (or the side lights) should be switched off after switching off the ignition contact. With this circuit, there should be no dead battery due to headlights that were left on.
Second, to indicate that the head lights should be on once ignition contact is switched on.

Car Headlight Alarm Features:

• Continuously repeated alarm tone for lights ON (may be disabled)
• Repeated alarm tone for lights OUT
• Only 3 wires are required for hook-up

Download the manual of Car Headlight Alarm here (you may buy the kit at electronickits.com with price of US$19.95)

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Sensitive FM Transmitter circuit diagram

Simple and easy build of FM transmitter circuit. The circuit only require 2 transistors.

Circuit Notes:
Typically the default for the capacitors model is ceramic, preferably the npo 1% type or equivalent. However , generally almost nothing critical right here. Work with any capacitor you’ve laying arround, but DO NOT use any electrolytic or tantalum capacitors. Only in case you intend to apply this circuit outside the home you may need to use capacitores which have more temperature stability.

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Low Voltage Alarm Circuit Schematic With explanation

This low voltage circuit can be used to monitor batteries and other volatile sources of current for problems. The circuit sounds an alarm and lights an LED, but can be interfaced to any number of other circuits for many different uses.'

Parts

Part Total Qty. Description Substitutions R1, R3 2 1K 1/4W Resistor R2 1 5K Pot U1 1 LM339 Op Amp IC D1 1 1N5233B Zener Diode D2 1 LED BZ1 1 Piezo Buzzer MISC 1 Board, wire, socket for IC

Notes

1. The circuit will operate from 9V to 12V.
2. Adjust R2 until the alarm goes off at the correct voltage.s
3. \

Source : aaroncake.net/

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Digital Keypad Combination Lock Circuit Schematic with explanation

This simple circuit is the electronic version of the combination lock. Using the special purpose LS7220 digital lock IC, the circuit allows a 4 digit combination of your choice to activate a relay for a set period of time. This relay can then be used to trigger a lock solenoid, enable a starter button, open a motorized door, or many other tasks that require a momentary signal.

Parts

Part Total Qty. Description Substitutions C1 1 1uF 25V Electrolytic Capacitor C2 1 220uF 25V Electrolytic Capacitor R1 1 2.2K 1/4W Resistor Q1 1 2N3904 NPN Transistor 2N2222 D1 1 1N4148 Rectifier Diode 1N4001-1N4007 K1 1 12V SPDT Relay Any appropriate relay with 12V coil U1 1 LS7220 Digital Lock IC S1-S12 12 SPST Momentary Pushbutton Keypad (see notes) HD1 1 12 Position Header

Notes

1. To set the combination, wire the appropriate switches to U1 pins 3, 4, 5 and 6 using the header. For example if S1 was connected to pin 3, S2 to pin 4, S3 to pin 5 and S4 to pin 6, the combination would be 1,2,3,4. Now wire all other unused switches across the header to pin 2 of U1. In this way you can create any 4 digit combination you want. Pin 2 is the reset pin, so connecting all unused keys to it assures that the entire combination must be reentered if an incorrect key is pressed.
2. When the appropriate combination is entered, the relay is activated for a period of time determined by C1. The 1uF capacitor specified in the parts list will result in an on-time of roughly 5 seconds. Increase the value of C1 to increase this time.
3. An easy way to make a keypad is to buy 12 PC board mount pushbuttons and then etch a PC board so that the buttons are in 4 rows of 3, similar to a telephone keypad. Place this in a case and then use a label maker or transfer letters to add your numbers to the tops of the pushbuttons. You can also use a pre made keypad but keep in mind that you need a pad which provides an output for each key. Most pads available have the keys connected to provide a row and column signal when they are pressed.

Source: www.aaroncake.net

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