Description:
This is a circuit intended to be used in basketball shot clock.
Circuit diagram
Notes:
To start in 24 seconds; 24s LOAD SW and Reset SW should be push
simultaneously. If not, the count will start in 99. Pulse input can be
connected to 555 astable multivibrator but must be calibr
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Description. The circuit shown here is of a simple 0 to 9 display that can be employed in a lot of applications. The circuit is based on asynchron...
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Batteries charger & PSU - ideal for digital cameras Circuit
Circuit diagram
This circuit was created for digital cameras. It's known the digital
cameras have considerable power consumption. For example my camera
Minolta E223 requires approximately 800 mA. In practice a mains power
supply or high capacity NiMH accumulators (batteries) can satisfy thi
5+LAMP+LED+FLASH+DRIVER.gif)
5 Lamp / LED Flash Driver
5+LAMP+LED+FLASH+DRIVER.gif)
Description
General Description of the following circuit. This circuit is based around HT–2050 manufactured by HOLTEK semiconductors. It is a low cost, low-power C-MOS LSI designed for lamp andLED flash driver. It requires minimum external components.You can operate it with just two AAA c
12V to 220V Inverter 180W by 2N3055
This is AC Inverter circuit ,It Converts 12VDC to 220VAC Output 180W. Use easy Circuit Square Wave Oscillator Generator 50Hz.
So Boost up Current High by 2N3055 Drive Transformer output 220V 50HZ From Voltage Supply 12V 10A.
This circuit is converter to use to charge DC12V from the lead-acid
ba
Mic-Line Balance input
A professional
suggestion for those interested in improving sound. The circuit constitutes the part of
input mixing console sound from the microphone or source of high level . It can be used on
it's own or be multiplied to the number of channels required. It
Sound Level Meter
This nifty sound level meter is a perfect one chip replacement for the
standard analog meters. It is completely solid state and will never wear
out. The whole circuit is based on the LM3915 audio level IC and uses
only a few external components. This circuit can also be integrated into
audio
Crystal Radio
I have received a number of emails regarding schematics for crystal
radios. After about the third email, I figured that I may as well put
one on my page. So here it is. The circuit is very simple with only 5
parts, but performs very nicely when used with the right size antenna.
Charger for mobile phones
Description
Most mobile chargers do not
have current/voltage reguLation or short-circuit protection. These
chargers provide raw 6-12V DC for charging the battery pack. Most of the
mobile phone battery packs have a rating of 3.6V, 650 mAh. For
i
Phone Busy Indicator
Have you ever been using the modem or fax and someone else picks up the
phone, breaking the connection? Well, this simple circuit should put an end to
that. It signals that the phone is in use by lighting a red LED. When the phone
is not in use, a green LED is lit. It needs no external power a
100W MOSFET power amplifier
A 100W MOSFET power amplifier circuit based on IRFP240 and IRFP9240
MOSFETs is shown here. The amplifier operates from a +45/-45 V DC dual
supply and can deliver 100 watt rms into an 8 ohm speaker and 160 watt
rms into a 4 ohm speaker. This Hi-Fi amplifier circuit is suitable for a
lot applic
State Variable Filters
With the advancement in IC technology,
a number of manufacturers now offer universal filters having
simultaneous low-pass, high-pass, and band-pass output responses. Notch and all-pass functions are also available by combining these output responses in the
uncommitted op-amp. Because of its ve
5 to 30 Minute Timer
Descriptipn:
A switched timer for intervals of 5 to 30 minutes incremented in 5 minute steps.
Circuit diagram
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
DC Motor Reversing Circuit
Description:
A DC motor reversing circuit using non latching push button switches.
Relays control forward, stop and reverse action, and the motor cannot be
switched from forward to reverse unless the stop switch is pressed
first.
Circuit diagram
Notes:
At first glance this may look
DC or AC Voltage Indicator Circuit
Description
This circuit is not a novelty, but it proved so useful, simple and
cheap that it is worth building. When the positive (Red) probe is
connected to a DC positive voltage and the Black probe to the negative,
the Red LED will illuminate. Reversing polarities the Green LED w
ZN414 Portable AM Receiver
Notes:
Designed around the popular ZN414 ic this receiver covers the AM band
from 550 - 1600 KHz with the values shown. For Longwave the coil needs
to be changed. Use one from an old MW radio to save time. The ZN414 is a
tuned radio frequency designed and incorporates several RF stages and
an
Electronic Security Door Key
Circuit
Description
A different circuit of electronic lock very simple, one and does not
need a lot of materials in order to it is manufactured. The right keys
of code should be stepped with the right line, so that is activated the
optocupler IC2. If from error is stepped switch that does no
Capacitance Meter
Circuit diagram
Position Range
a 1 uf
b 100 nf
c 10 nf
d 1 nf
e 100 pf
Use X10 switch to measure up 10uf.
Use X0.5 switch for better readings on low values.
This project is
more complex than the others described earlier. However, when finished,
you will have an instrument capable of
500W low cost 12V to 220V inverter
Using this circuit you can convert the 12V dc in to the 220V Ac. In this
circuit 4047 is use to generate the square wave of 50hz and amplify
the current and then amplify the voltage by using the step transformer.
Circuit diagram
How to calculate transformer rating
The basic for
Temperature-Controlled Switch
Description
It sounds rather mysterious: a switch that is controlled by its ambient temperature. All without the touch of a human hand, except for when you’re building this sort of electronic thermostat. There are a lot of handy uses for a thermally controlled switch. If the temperature inside yo
Whistle Responder Schematic - Circuit Diagram
Description
Some 20 years ago it was common to see small key-holders emitting an intermittent beep for a couple of seconds after its owner whistled. These devices contained a special purpose IC and therefore were not suited to home construction. The present circuit is designed around a general p
Stereo Preamplifier with Bass-boost
circuit diagram:
Comments:
This preamplifier was designed to cope with CD players, tuners, tape recorders etc., providing a gain of 4, in order to drive less sensitive power amplifiers. As modern Hi-Fi home equipment is frequently fitted with small loudspeaker cabinets, the bass frequency range
24 Hour Timer
Description:
These two circuits are multi-range timers offering periods of up to 24 hours and beyond. Both are essentially the same. The main difference is that when the time runs out, Version 1 energizes the relay and Version 2 de-energizes it. The first uses less power while the timer is runni
73 MHz Hallogene Lamp Radio-Controlled
Circuit diagram
This circuit is a 73 MHz Hallogene Lamp Radio-Controlled. The purpose of it is to control the power state of a hallogene lamp by a remote control. When we press the push botton of the remonte control, the power state of the lamp will be changed, so, if the lamp was turned on, it
RF Amplifier Wide Band (40MHZ)
The sensitivity of receiver it is possible to increase itself considerably, if is interfered, between this and his aerial, a amplifier RF. The amplifier of circuit, does not use in resonant circuits and for this is suitable, so much for mid waves, what for the low waves, up
Alternative Halogen Power Supply
Description
Readers who do not care to modify the power supply of an old PC into a suitable halogen power source (see our April 2006 issue), may find the present design a welcome alternative. The circuit does not need any changes to the power supply. It allows the halogen lamps to be initially
Frequency Doubler with 4011
Description
This frequency doubler uses one CMOS quad, two input NAND gate package type 4011. The frequency doubler proper consists of an inverter IC1B, two differentiating networks R1/C1, R2/C2 and NAND gate IC1A, IC1C and IC1D function as input and output buffers. In Fig.2 exist the pulses in
Telephone
The Link "P" - Privacy Link! (Telephone Intercom)
Yes folks, it's time for another horse to bolt from the Downunder stable of telephone intercoms (unfortunately before the gate could be shut on it...) and other zany electronics type ideas. The circuit you are about to see is the culmination of some effort at improving the basic Link intercom
