his circuit provides a simple means to determine the voltage of a low-impedance voltage source. It works as follows. P1, which is a 1-W potentiometer, forms a voltage divider in combination with R1. The voltage at their junction is buffered by T1, and then passed to reference diode D1 via R3. D1 limits the voltage following the resistor to 2.5 V. An indicator stage consisting of T2, R4 and LED D2 is connected in parallel with D1. As long as the voltage is not limited by D1, the LED will not be fully illuminated. This is the basic operating principle of this measurement circuit.
Saturday, 8 November 2014
Friday, 7 November 2014
Bass Booster Circuit
Bass Boost is todays sound... whether its the driving, gut-vibration pulsation of disco, or the solid bass line of soft, hard, or laid-back rock. One way to get the modern bass-boost sound without running out and buying an all-new expensive piece of equipment is to use a Bass Booster between your guitar, electronic organ or what-have-you, and the instrument amplifier. A bass booster strips the highs from the instruments output signal and amplifies low frequencies, feeding on "all-bass" sound to the instrument amplifier. Naturally, the bigger the speaker used with the amp, the more powerful the bass: use 15-inchers with the Bass Booster and you can rattle the windows. Bass Booster is powered by an ordinary 9 volt transistor radio battery. It can be assembled on a small printed board or on a veroboard using point to point wiring. The booster connects between your instrument and its amplifier through two standard RCA Jacks.
Circuit diagram:
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Circuit diagram:
Voltage to pulse Duration Converter Circuit Diagram
This is a circuit of Voltage-to-Pulse Duration Converter. This circuit is used to convert voltage into pulse duration by combining a timer IC and an OP Amp. Accuracies to better than 1% can be obtained with this circuit (a), and the output signals (b) still retain the original frequency, independent of the input voltage.
Voltage-to-pulse Duration Converter Circuit Diagram
Thursday, 6 November 2014
Smart Trailing Socket
Mains sockets switched automatically by a Control Socket, Up to 1000W switched power
This circuit consists of a Trailing Socket (also called Extension or Distribution Socket) or similar device where two, three or more sockets (depending on the box dimensions and on constructors needs) will be powered only when a current flows in the Control Socket. For example: if an electric drill is connected to the Control Socket, the Switched Sockets will be powered each time the electric drill is running. In this case, a lamp could be connected to a Switched Socket and will illuminate when the drill is operating. Another example: a desk lamp could be connected to the Control Socket and a PC, a Monitor and a Printer could be connected to the Switched Sockets and will be running after the lamp is switched on. Switching off the lamp, all the above mentioned appliances will be automatically switched off. A further application is the control of a High Fidelity chain, plugging the Power Amplifier in the Control Socket and - for example - CD Player, Tape Recorder, and Tuner in the Switched Sockets.
Usually, trailing sockets are placed to the rear of the appliances, often in places not easily reachable, so, even if the socket has a switch, it is much easier to switch on and off the High Fidelity chain from the main amplifier itself. The same consideration is valid for computer-monitor-printer chains etc. Nevertheless, in this case, the use of a table lamp plugged in the Control Socket is almost mandatory, as explained below. In fact, this very sensitive circuit works fine when appliances having full breaking switches like lamps, drills, most power amplifiers, old radios, old TV sets, fans, almost all electrical household appliances etc. are plugged in the Control Socket. This is because these devices have a switch that fully excludes the internal circuitry from the mains. Unfortunately, in modern devices like computers, monitors, CD players, recent radios and TV sets (usually powered by means of internal "switching" supplies), the power switch does not completely isolate the internal circuitry from the mains, as transient suppressors and other components remain on circuit. This causes a very small current to flow across the sensing circuitry, but sufficient to trigger the output Triac.
Therefore, the switched devices will remain always on, no matter if the control appliance is on or off. This could also happen when devices connected to the mains by means of plug-in power supply adapters are used as control appliances, due to their lack of a mains switch. In spite of this restriction, the circuit can be still useful, due to the high number and variety of devices allowing impeccable performance when they are plugged in the Control Socket.
Smart Trailing Socket Circuit Diagram
Parts:
R1,R2_________100R 1/2W Resistors
C1____________100nF 630V Polyester Capacitor
D1 to D6_____1N5408 1000V 3A Diodes (See Notes)
D7__________TIC225M 600V 8A Sensitive Gate Triac (See Notes)
A commercial trailing socket to be modified or a self-made box with several sockets.Circuit operation:
Six back-to-back power diodes are connected in series to the Control Socket. The current drawn by the device plugged into this socket when in the on state, flowing through the diode chain, causes a voltage drop of about 2V. This voltage, limited by R1, drives the Gate of the Triac D7 which, in turn, will switch the output sockets. C1 and R2 form a so called "Snubber network", helping to eliminate switching transients generated by inductive loads.
- The circuit is sufficiently small to be embedded into some types of commercial trailing sockets, or a box with a number of sockets can be made at will.
- The diode types suggested in the Parts List for D1 to D6 will allow an appliance of up to about 500W power to be plugged in the Control Socket. Use BY550-800 diodes for up to 800 - 1000W.
- For less demanding appliances, 1N4007 diodes will allow up to 200W power.
- The Triac type suggested in the Parts List for D7 will allow a total power available to the Switched Sockets of more than 1000W. If you intend to drive loads of more than 500W total, please use a suitable heatsink.
- Wanting to drive less powerful loads, you can use for D7 a TIC216M (up to 800 - 1000W) or a TIC206M (up to 500 - 600W).
- Warning! The device is connected to 230Vac mains, so some parts in the circuit board are subjected to lethal potential! Avoid touching the circuit when the mains cord is plugged in!
Simple Treble Tone Control
The treble control works in a similar manner as the bass control elsewhere in this site, but contains several modifications, of course. One of these is the series network C1-C2– R1– R1 1. The d.c. operating point of IC3 is set with resistors R12 and R13. To ensure that these resistors do not (adversely) affect the control characteristics, they are coupled to the junction of R9 and R1 0. In this way they only affect the low-frequency noise and the load of the opamp. Their value of 10 kΩ is a reasonable compromise. The functions of switches S1– S3 are identical to those of their counterparts in the bass tone control; their influence is seen clearly in the characteristics.
Treble Tone Control Circuit diagram:
Good symmetry between the left-hand and right-hand channels is obtained by the use of 1% versions of R1– R1 3 and C1, C2. The value of resistors R2– R1 0 is purposely different from that of their counterparts in the bass tone control. In the present circuit, the control range starts above 20 kHz. To make sure that a control range of 1 0 dB is available at 20 kHz, the nominal amplification is 3.5 (11 dB ). The control circuit draws a current of about ±10 mA.
