Sunday, 31 March 2013
Indoor and Outdoor Temperature Controller
In principle of work this circuit is when the Q1 to the ground voltage by less than half of supply voltage (determined by R7 & R9), the voltage generated in the R8 and the driver transistors Q2 & Q3-switch on the relay. Two sensors required, one placed outside the home, to sense an external temperature. When Q1 Base voltage to the ground more than half of the voltage supply, caused when one of NTC thermistor low value because of the increase in temperature, voltage does not appear in the R8 and the Relay is not active. C3 allows clean switching of Relay. P1 functions as the main temperature control.
Part:
P1 = 1K Linear Potentiometer
R1 = 10R
R2 = 1K
R3 = 3K3 @ 20°C n.t.c. Thermistor
R4 = 2K2 @ 20°C n.t.c. Thermistor
R5 = 10K
R6 = 3K3
R7,R9 = 4K7
R8 = 470K
R10 = 10K
C1,C2 = 470µF 25V
C3 = 1µF
D1,D2,D4 = 1N4002
D3 = LED Red
Q1 = BC557
Q2 = BC547
Q3 = BC337
RL1 = Relay with SPDT 2A @ 220V switch
Coil Voltage 12V. Coil resistance 200-300 Ohm
T1 = 220V Primary, 12 + 12V Secondary 3VA Mains transformer
Friday, 29 March 2013
Joulethief SEC exciter and variants
That coil wire(~0.25mm) is wound around conical pendant cap(cup?). Not sure what it is called in english language. Anyways, the cap, that hides the pendants electrical connections on the upper side.
Approximate coil dimensions:
Lighting the cfl:
The basic circuit, with an additional transistor:
I have no particular reason to use that additional transistor, just a thought, that it might halve the strain, per transistor. Just as using two power resistors in parallel.
That configuration seems to increase the output of the circuit or coil.
Resulting bright cfl, and also a plasma stream, simultaneously, that wasnt the case with one transistor.
At the expense of the transformer(Canon bubblejet 5V/200mA), that gets pretty warm, when testing that t2-schema.
After all, I really like to run this circuit on 5 volts, and will look, if I can purchase some overkill power transistors.
I already have an ancient PC psu, that can deliver 15A/5V.
One might wonder, what is it, that Im after with all this?
Its simply that plasma thing, very new thing to me, and Im looking the way to get the most out of it. Possibly use it in productive, and creative manner.
Wednesday, 27 March 2013
Non Contact Power Monitor circuit
Here is a simple non-contact AC power monitor for home appliances and laboratory equipment that should remain continuously switched-on. A fuse failure or power breakdown in the equipment going unnoticed may cause irreparable loss. The monitor sounds an alarm on detecting power failure to the equipment. The circuit is built around CMOS IC CD4011 utilising only a few components. NAND gates N1 and N2 of the IC are wired as an oscillator that drives a piezobuzzer directly. Resistors R2 and R3 and capacitor C2 are the oscillator components. The amplifier comprising transistors T1 and T2 disables the oscillator when mains power is available. In the standby mode, the base of T1 picks up 50Hz mains hum during the positive half cycles of AC and T1 conducts.
Circuit diagram:
Non-Contact Power Monitor circuit diagram
This provides base current to T2 and it also conducts, pulling the collector to ground potential. As the collectors of T1 and T2 are connected to pin 2 of NAND gate N1 of the oscillator, the oscillator gets disabled when the transistors conduct. Capacitor C1 prevents rise of the collector voltage of T2 again during the negative half cycles. When the power fails, the electrical field around the equipment’s wiring ceases and T1 and T2 turn off. Capacitor C1 starts charging via R1 and preset VR and when it gets sufficiently charged, the oscillator is enabled and the piezobuzzer produces a shrill tone. Resistor R1 protects T2 from short circuit if VR is adjusted to zero resistance.
The circuit can be easily assembled on a perforated/breadboard. Use a small plastic case to enclose the circuit and a telescopic antenna as aerial. A 9V battery can be used to power the circuit. Since the circuit draws only a few microamperes current in the standby mode, the battery will last several months. After assembling the circuit, take the aerial near the mains cable and adjust VR until the alarm stops to indicate the standby mode. The circuit can be placed on the equipment to be monitored close to the mains cable.
Monday, 25 March 2013
4x25W CAR AMPLIFIER TDA7381 ELECTRONIC DIAGRAM
The extremely reduced components count allows very compact sets. The on-board clipping detector simplifies gain compression operations. The fault diagnostics makes it possible to detect mistakes during Car- Radio assembly and wiring in the car.
Absolute maximum ratings of IC TDA7295 IC
- Operating supply voltage = 18 V
- DC supply voltage = 28 V
- Peak supply voltage (t = 50 ms) = 50 V
- Output peak current Repetitive (duty cycle 10 % at f = 10 Hz) = 3 A
- Output peak current Non repetitive (t = 100 µs) = 4A
- Power dissipation, (Tcase = 70 °C) = 80 W
- Junction temperature = 150 °C
- Storage temperature = -40 to 150 °C
Saturday, 23 March 2013
Incubator and Manual
This is normal and indicates that the incubator is adjusting to changes in both internal and external air temperatures. Run the incubator for 6-8 hours. At the end of this time, make sure the desired temperature was maintained. If so, you are ready to incubate!
Disassembly: Place complete Automatic Egg Turner on a flat surface. Slide power cord horizon- tally to remove from notch in base. Loosen two screws connecting the motor to base and remove. Slide motor upward, releasing the white plastic lever from T- bracket of connecting rod. Turn connecting rod so offset arms rest in a horizontal position and egg trays are vertical. Lift offset arm to release con- necting rod from notches. Lift individual egg trays by offset arms while still in a horizontal position from offset arm notch in base and pull slightly to release the pin from the corresponding hole in the base.
Repeat with all six trays until you are left with an empty base. Place egg trays and base in dishwasher, run and dry. manual can be found here