Friday, December 12, 2014
Wireless IR headphone receiver schematic
6v 12vdc converter circuit
For example, you could run 12V car accessories in a 6V (British?) car.he circuit is simple, about 75% efficient and quite useful.
By changing just a few components, you can also modify it for different voltages.
Transistor Checker
This simple circuit can check transistors, in the circuit, down to 40 ohms across the collector-base or base-emitter junctions. It can also check the output power transistors on amplifier circuits. Circuit operation is as follows. The 555 timer ( IC1 ) is set up as a 12hz multi vibrator.
The output on pin 3 drives the 4027 flip-flop ( IC2). This flip-flop divides the input frequency by two and delivers complementary voltage outputs to pin 15 and 14.
Thursday, December 11, 2014
D I Y Gold Detector Schematic
Here the very simple and easy build gold detector circuit.The circuit capable to sense gold or metal or coins from a distance of about 20cm, depending on the size of the object to detect.The circuit oscillates at ab out 140kHz and a harmonic of this frequency is detected by an AM radio.You can simply tune the radio receiver until a squeal is detected.
Thursday, November 20, 2014
Troubleshooting STR IC Regulator Power Supply
A. Unable to start.
Read More..
Can be caused by:
- No start-up voltage supply Vcc or a voltage less than 16V
- Electrolityc Capacitors supply voltage Vcc filter dry.
2. Led indicator blinking
If the supply voltage Vcc examined rocking. This is because the regulator of life and death because OVLO work., Die-protectionist regulators and auto start life over and over. If it is turned off Electrolityc Capacitors usually still keep the rest of the cargo.
Can be caused by:
- Electrolityc Capacitors supply voltage Vcc filter on a pin-4 dry. Replace with a value equal to or slightly larger. - triger UVLO
- input filter capacitor on pin-1 feed dry behind the declining value - triger OLP
- Rectifier diode of the switching transformer is damaged (sometimes when examined with avo-meter looks like a still good)
- cause the supply voltage Vcc drops of the switching transformer (UVLO)
- Part damage or broken lines on the feedback circuit of the voltage regulator through B to photocoupler - triger OVP
- Electrolityc Capacitors dry filter voltage B - triger OVP
- One of the output voltage of the switching transformer secondaries there is a short (over load) - triger OLP
- Soft start capacitor value decreases - triger OLP
3. Noise arising (noise)
Can be caused by:
- Transformer windings slack.
- If there are ceramic capacitors - can sometimes cause interference noise due to its characteristic piezoelectrik like crystal resonator. Replace with film capacitors.
4. When the st-by normal stress. But when the power is on the regulator directly off protectionism no voltage on the secondary this part. Electrolityc Capacitors are still storing charge.
Can be caused by:
- Sensor OVP small value resistor on pin-2 to the ground so that the value of delayed triger to OLP or OCP.
- Regulator IC is damaged
Excellent Electronics Heterodyne Detector
The bat ultrasounds are best up by the microphone SPKR1 and go through two stages of addition at Q1 and Q2. Separately, a tunable (R12) distinct abundance is produced by the LM567 oscillator U1. The LM567 is a accent decoder but actuality its ascribe is ashore and its voltage controlled oscillator is acclimated as a attention oscillator. The oscillator abundance is accustomed by
f = 1/(1.1*C4*(R10 + R12))
= 1/(1.1*0.0022*10-6*(4.7 + [0-50])*103)
= [88-7.5] khz
The two signals are alloyed at Q3 to aftermath both a arresting in the audio ambit and college frequencies that are again filtered out.
The actual audio arresting undergoes a aftermost date of controlled (R13) addition with the LM386 at U2 afore actuality accessible for achievement at AUDIO OUT. The ability antecedent is a simple 9V battery, so this apparatus is absolutely portable.
Wednesday, November 19, 2014
Active Crossover 2 Way Schematics
Therefore this architecture represents the simplest access I could booty and still get the adapted outcome.The band akin audio arresting enters the absorber area it is astern out of phase.This is to atone for the filters which will alter the appearance afresh appropriately abiding the arresting to it’s able phase. The filters are more-or-less accepted low and aerial canyon filters appropriately however, added capacitors and resistors accept been added in adjustment to get the altruism bottomward to a minimum appliance alone E12 components.
This alive Cantankerous over is adequately beeline forward. It consists of a absorber and two 3rd order, 18 dB per octave filters. One low canyon and the added high. The cantankerous over abundance is set at 2Khz and is advised for AEK’s 400watt per access PA/Keyboard Amp systems. Obviously alone one access is apparent here.
This ambit may not be of awfully abundant use to anyone as it was accurately advised to clothing the applications. It is not capricious or switchable for two reasons. Firstly, it didn’t charge to be back the backdrop of the apostle arrangement were already known. And secondly, the added complication was put into the accurateness of the crossover rather than it’s flexibility. The filters are akin in account to anniversary added as able-bodied as can be accepted appliance alone E12 components. If switching were to be active to accord a ambit of abundance options, a accommodation would accept to be fabricated on clarify accuracy.
The alone added way to accomplish a accepted crossover architecture and advance accurateness would apparently be to use Switched capacitor clarify architecture blocks. In theory, two 18or 24dB per octave filters could be complete such that they tracked anniversary added by actuality bound to the aforementioned clock. This would be a nice agreement but I haven’t had the befalling to prove this technology for this affectionate of application. My primary affair was the breach through of switching babble appliance such a design.
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