Video Amplifier by transistor BC547 & BC557 2007-05-22 11:28:17 Circuit Video Amplifier
by transistor BC547 & BC557
PCB Video Amplifier by transistor BC547 & BC557
circuit, Power supply circuit, Pre AmplifierShare This
Sound SCR Swith by IC 1458 & SCR C106D 2007-05-22 11:17:39 Circuit Sound
SCR Swith by IC 1458 & SCR C106D
PCB Sound SCR Swith by IC 1458 & SCR C106D
circuit, circuit switches, Electronic ControlShare This
Light Relay Switch By BC547 & BC337 2007-05-22 11:15:14
Circuit Light Relay Switch By BC547 & BC337
PCB Light Relay Switch By BC547 & BC337
circuit, circuit switches, Electronic ControlShare This
Circuit power supply regulator +15V +30V -15V -30V 1 A by Transistor C1061 & 2N3053 2007-05-21 12:45:52 Circuit power
supply regulator +15V +30V -15V -30V 1 A by Transistor C1061 & 2N3053
PCB power supply regulator +15V +30V -15V -30V 1 A by Transistor C1061 & 2N3053
2N3053, blogger, C1061, circuit, Power supply and Inverter, Power supply circuit, power supply, regulator, transistorShare This
Read more:Circuit
L200 Current Limiting Power Supply 2007-05-25 12:36:37 Circuit : Ron J
Email Ron
Source : http://www.zen22142.zen.co.uk/Circuits/Power/clps.htm
Description:
This is a 1-amp variable-voltage PSU. It adjusts from about 3v to 24v: and has the added feature that you can limit the maximum output current. This is invaluable when (for example) you power-up a project for the first time or soak-test a piece of equipment.
Notes:
SW3 is the on/off switch. It also lets you choose between the output with the current limit and the one without. SW2 provides a selection of three different limits. You can increase or decrease this number if you wish. The limits are fixed by R4, R5 & R6. They are set at 10mA, 25mA & 65mA respectively; but you can choose whatever limits you like. If you try to draw a current above the limit you’ve selected, the output voltage will fall. Thus, the voltmeter indicates when the load on the output is excessive.
The housing should be well ventilated. The heatsink is a folded strip of aluminium about 2mm thick, 18cm Read more:Current
, Limiting
, Power Supply
, Supply
2 Transistor (BC548) FM Voice Transmitter 2007-05-25 12:22:32 Source :: http://www.zen22142.zen.co.uk/Circuits/rf/2bjttx.htm
Take care with transmitter circuits. It is illegal in most countries to operate radio transmitters without a license. Although only low power this circuit may be tuned to operate over the range 87-108MHz with a range of 20 or 30 metres.
Notes:
I have used a pair of BC548 transistors in this circuit. Although not strictly RF transistors, they still give good results. I have used an ECM Mic insert from Maplin Electronics, order code FS43W. It is a two terminal ECM, but ordinary dynamic mic inserts can also be used, simply omit the front 10k resistor. The coil L1 was again from Maplin, part no. UF68Y and consists of 7 turns on a quarter inch plastic former with a tuning slug. The tuning slug is adjusted to tune the transmitter. Actual range on my prototype tuned from 70MHz to around 120MHz. The aerial is a few inches of wire. Lengths of wire greater than 2 feet may damp oscillations and not allow the circuit to work. Althoug Read more:Transmitter
, Voice
Power Supply Regulator by IC L200 2007-05-25 11:58:07 Circuit : Andy Collinson
Email: anc@mitedu.freeserve.co.uk
Source : http://www.zen22142.zen.co.uk/Circuits/Power/l200.html
Power supply with voltage and current regulation built around the L200C regulator.
Notes:
The versatile 5 pin L200C regulator offers both voltage and current regulation in a single package. The IC also features thermal shutdown and input over voltage protection up to 60 Vdc. The package is also available as L200CV which has straight pins for mounting onto a PCB.
Specifications:
DC Input Voltage: 40V max.
Peak Input Voltage: 60V max. for 10ms
Output Voltage Range: 2.85 to 36V
Output Current Range: 0.1 to 2A
Quiescent Current: 4.2mA
Output Noise: 80uV
circuit, L200, Power supply circuit, regulatorShare This
Read more:Power Supply
, Regulator
, Supply
Boosting Regulator Current for IC 78xx by MJ2955 2007-05-25 11:48:30 Source :: http://www.zen22142.zen.co.uk/Circuits/Power/boosti.htm
IC 78xx series of voltage regulators are available with different current outputs, you can boost
the available current output with this circuit. A power transistor is used to supply extra current to the load
the regulator, maintaining a constant voltage. Current
s up to 650mA will flow through the regulator, above
this value and the power transistor will start to conduct, supplying the extra current to the load. This should
be on an adequate heat sink as it is likely to get rather hot. Suppose you use a 12v regulator, 7812. The
input voltage should be a few volts higher to allow for voltage drops. Assume 20 volts. Lets also assume
that the load will draw 5amps. The power dissipation in the transistor will be Vce * Ic or (20-12)*8=40watt.
It may keep you warm in the Winter, but you will need a large heatsink with good thermal dissipation.
If you want to Boost the output current with a negative regulator, such as the 79x Read more:Regulator
IC LM723 - Voltage Regulator 2007-05-25 11:37:13
Features
•
150 mA output current without external pass transistor
•
Output currents in excess of 10A possible by adding external transistors
•
Input voltage 40V max
•
Output voltage adjustable from 2V to 37V
•
Can be used as either a linear or a switching regulator
General Description
The LM723/LM723C is a voltage regulator designed primarily for series regulator applications Source :: http://www.national.com/pf/LM/LM723.html
Datasheets, LM723, Power supply and Inverter, Power supply circuit, regulatorShare This
Read more:Regulator
, Voltage
Super Small Amp 1.2W by IC TDA7052 2007-05-25 04:10:46
Circuit SuperSmall
Amp 1.2W by IC TDA7052
PCB Super Small Amp 1.2W by IC TDA7052
car power amplifier, circuit, Power Amplifier, TDA7052Share This
Pre MIC (microphone preamplifier) 3 CH by IC LM348 2007-05-25 04:04:47
Circuit Pre MIC (microphone
preamplifier) 3 CH by IC LM348
PCB Pre MIC (microphone preamplifier) 3 CH by IC LM348
LM348, microphone preamplifier, Pre Amplifier, Pre MICShare This
Pre Tone Control Stereo by IC NE5532 2007-05-25 03:55:41 Circuit Pre Tone ControlStereo
by IC NE5532
PCB Pre Tone Control Stereo by IC NE5532
circuit, NE5532, Power Amplifier, Pre Amplifier, Tone controlShare This
iPods Implicated in Pacemaker Malfunctions 2007-05-25 01:47:28 A study by an Okemos High School student in conjunction with several doctors has concluded that iPods can interfere with the functioning of pacemakers. Holding the iPod in proximity to the pacemaker caused malfunctions in 50% of patients tested.
The iPods caused the pacemakers to record incorrect telemetry and in one case caused one to stop working. The researchers are concerned that this interference could lead doctors to misdiagnose heart conditions based on the pacemaker’s telemetry.
“It’s clear that iPods can affect pacing function. There is a possibility for a severe reaction, such as loss of consciousness,” said Dr. Edwin Kevin Heist, a cardiac electrophysiologist at Massachusetts General Hospital.
Source: www.dailyindia.com
ipods, news of today, News TechnologyShare This
Other gates made with NAND 2007-05-29 03:52:21 Source :: http://www.doctronics.co.uk/4011.htm
An important property of NAND gates is that they can be linked to perform the functions of other logic gates. In fact, any logic function can be implemented using only NAND gates:
If you have designed a system which needs a NAND gate, a NOT gate and an AND gate, you might think of using a separate integrated circuit for each logic function. This would leave you with a circuit in which there were three unused NAND gates, five unused NOT gates and three unused AND gates. It is a lot more efficient (and cheaper) to use NAND gates to implement the other functions. All three gates can be made with just one 4011 integrated circuit.
4011, basic electronics, circuit, digitalShare This
4011 : 2-input NAND gates (easy IC ) 2007-05-29 03:33:53 Source :: http://www.doctronics.co.uk/4011.htm
Pin connections
The 4011 has four separate 2-input
NAND
gates which you can use independently.
Truth table
The truth table of each individual gate is:
input B
input A
output
0
0
1
0
1
1
1
0
1
1
1
0
where ‘0′ represents a LOW voltage, and ‘1′ represents a HIGH voltage.
4011, basic electronics, Datasheets, digitalShare This
circuit power amp OTL 100W by transistor 2N3055 (with PCB) 2007-05-29 03:18:04 This is Circuit Power Amp OTL 100W by transistor 2N3055.
It easy to build because normal circuit power
amp OTL.
To use power supply 98V 5A.
Out put power 100W at Speaker 8 OHM or 120W : 4OHM.
circuit power amp OTL 100W by transistor 2N3055 (with PCB)
circuit Power Supply 98V 5A FOR power amp OTL 100W by transistor 2N3055 (with PCB)
PCB power amp OTL 100W by transistor 2N3055 (with PCB)
2N3055, OTL AMP, Power Amplifier, power supplyShare This
power amp mosfet ocl 60W by K134 and J49 with PCB 2007-05-29 03:02:43 This is circuit power
amp mosfet ocl 60W, it use mosfet K134 and J49.
Out put power 60W at speaker 8 ohm or 120W at 4 ohm.
It easy circuit.
supply volt +49V gnd +49V ,Curent 3-5A.
circuit power amp mosfet ocl 60W by K134 and J49
PCB power amp mosfet ocl 60W by K134 and J49
K134 J49, Power Amplifier, Power Amplifier MOSFETShare This
Dark Activated Switch by IC 741 2007-05-29 02:18:53 Source :: http://www.zen22142.zen.co.uk/Circuits/Switching/darksw.htm
Circuit : Andy Collinson
Email: anc@mitedu.freeserve.co.uk
Description:
This circuit will activate a relay when light falls to a preset level. Light level can be adjusted with VR1 and the relay contacts may be used to operate an external light or buzzer.Notes:
The light sensor used is the ORP12 photocell. In bright light the resistance of the ORP12 can be as low as 80 ohm and at 50lux (darkness) the resistance increases to over 1 Mohm. The 1M control should provide a wide range for light intensities, if not its value may be increased. The op-amp senses the voltage difference between pins 2 and 3. The control VR1 is adjusted so that the relay is off, the output of the op-amp will be around 2 Volts. When light falls, the resistance of the photocell increases and the difference in input voltage is amplified by the op-amp, the output will swing towards full supply and drive the transistor and relay. The 270k resistor p
CD4001 Light Detector Circuit 2007-05-29 02:16:31 Source :: http://www.zen22142.zen.co.uk/Circuit
s/Switching/ldet.htm
Kindly submitted by Mick Devine from the UK
Notes:
Variable resistor R1 adjusts the light threshold at which the circuit triggers. R1’s value is chosen to match the photocells resistance at darkness. The circuit uses a CMOS 4001 IC. Gate U1a acts as the trigger, U1b and c form a latch. S1 resets the circuit. The output device may be a low power piezo buzzer.
4001, circuit, circuit switches, Lighting, picture circuitShare This
Read more:Detector
555 Timer 5 to 30 Minute 2007-05-29 02:01:02 Source :: http://www.zen22142.zen.co.uk/Circuits/Timing/5_30timer.htm
Circuit : Andy Collinson
Email: anc@mitedu.freeserve.co.uk
Descriptipn:
A switched timer for intervals of 5 to 30 minutes incremented in 5 minute steps.
Notes:
Simple to build, simple to make, nothing too complicated here. However you must use the CMOS type 555 timer designated the 7555, a normal 555 timer will not work here due to the resistor values. Also a low leakage type capacitor must be used for C1, and I would strongly suggest a Tantalum Bead type. Switch 3 adds an extra resistor in series to the timing chain with each rotation, the timing period us defined as :-
Timing = 1.1 C1 x R1
Note that R1 has a value of 8.2M with S3 at position “a” and 49.2M at position “f”. This equates to just short of 300 seconds for each position of S3. C1 and R1 through R6 may be changed for different timing periods. The output current from Pin 3 of the timer, is amplified by Q1 and used to drive a re Read more:Minute
, Timer
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