Led Flasher LOW VOLTThe following schematic is of the discrete component replacement for the LM3909. The values of the components were chosen to match those in the integrated circuit however resistor R5 is a guesstimate fit as the Q2 portion of the circuit as Q2 in the integrated circuit is a “current mirror” which is a type of [...]

Telephone In Use Indicator Here is a simple blinking LED circuit which will alert users when the line is in use before the receiver is lifted. The circuit loads the phone line so lightly that it meets the on-hook telephone equipment leakage specification and the short lamp flashes draw very little current from the nine-volt battery. One of these [...]

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Tap tempo circuit using ic cd4011 This circuit will have an effect than Tap the rhythm circuit other because the whistle is giddy, which vividly than usual knock. You can also adjust the speed with 10-40 strokes per minute. Operation of the circuit, we will be divided into three main parts of the schedule, the frequency generator, the control and amplify [...]

Music box automatically with IC UM66T This is an integrated music box Self Promotion Nat, when I open the music box to hear the music out. You can choose music in several voices, just change the IC number only. Operation of the circuit is when the power supply and switch S1. The IC IC1 is dozen, it will count clock is [...]

Music box versatile using IC M3481 This is a multi-purpose integrated music box that interesting, because an IC package. Is a simple and affordable. The main function of the circuit is the device of the circuit is IC1. This is a sound generator IC. The Christmas season. Its musical all 8 music. When the power supply LDR1 the exposure will cause [...]

Touch controlled musical bell using UM3481 This circuit produces a musical tone whenever someone touches the touch point designated as TP in the circuit. The circuit works from two AA cells and produces enough sound. The circuit uses IC UM 3481 commonly used in musical circuits. The IC contains a ROM with 512 musical notes, tone generator, rhythm generator, modulator, run [...]

Keyboard music circuit The work of the circuit this origin frequency sound circuit model astable multi vibrator. When build the circuit suits power supply the circuit will still don’t work. But if we press switch S1 the circuit will begin the work. By have current flow through R9 get along well with B of Q2, make Q2 begin

Create music with hand touch Operation of the circuit. In the normal range will not work Piezo Tweeter speakers on tap, but not the point of A Q1 Q2 will flow and the work of the bias voltage fall across R2. And the current flowing into pin 2 of IC1 IC1 make music production work out of three legs with [...]

Create music with ic UM66T Most circuits, we find that the IC number UM66T common because the smaller ICI power consumption of culture is not very easy. Choose music that has many songs together. Operation of the circuit when the power supply circuit are currents flowing through LED1 LED1 light and the electricity flowing into pin 2 of IC1 IC1 [...]

FM telephone bug Jun 18, 2010 … A simple telephone transmitter circuit that is ideal for transmitting the telephone conversation through small distances.The circuit is very simple …

Mobile Bug Detector using CA3130 Sep 6, 2010 … This handy, pocket-size mobile transmission detector can sense the presence of an activated mobile phone from a distance of one-and-a-half …

Bug Detector Circuit Mobile Bug Detector using CA3130. Monday, September 6th, 2010. This handy, pocket-size mobile transmission detector can sense the presence of an activated …

Telephone Listening Bug with FM Transmitter by A933 Mar 7, 2008 … Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio.

Telephone Listening Bug by A933 Jul 12, 2008 … Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio.

Bounceless Switch Apr 11, 2010 … This be simple bounceless switch circuit, In the character electronic switch a kind is one. That be of good quality tall and low noise convenient …

Simple bounceless switch using CD4049 This be simple bounceless switch circuit, In the character electronic switch a kind is one. That be of good quality tall and low noise convenient for the digital. If switch usual apply to digital circuit like to to get into trouble promise disturb easy. It make the circuit works can make a mistake. This circuit [...]

Simple Bounceless Switch by 4011 My friend want circuit Bounceless Switch,in testing digtal circuit. This is Simple Bounceless Switch by 4011 ( hot IC) The bounceless output have logic digital,it control by S1. Detail more, Please read in this image circuit.

Drive SCR thyristor by IC 555 This circuit gives a burst of pulses to fire 2 SCRs, when pin 4 is taken to 12V the SCR is turned on, to use this circuit you need 12V short pulses phase shifted with respect to AC sine wave on bridge. This way you can control the bridge from near 0% to near 100% [...]

Electronic (foot)switch by IC Digital This is a simple circuit for an electronic switch – I’d designed this for an external footswitch module but also with a duplicate button panel mounted. There are enough gates spare to easily make a dual version. Output – 0v to +V Gate (switchable Mom or Tog), plus trigger signal (c. 1ms pulse) each time [...]

Touch Switch By IC 4001 & 4020 Circuit Touch Switch By IC CD4001, CD4020 This be touch switch be simple again the circuit. It use integrated digital circuit is important equipment, and use volt power supply low just 9V. By use single metal, it works in the character turn ON and turn OFF. By when touch for the first time turn ON [...]

Transformerless Power Supply I have received a few emails asking for a transformerless power supply. Here is such a supply. This supply uses no heavy step down transformer and has an extremely low parts count. The circuit can be built very small and can supply small currents for small projects. The major downfall of this supply is that [...]

Power Supply 9VDC no transformer This is circuiut power supply 9VDC no transformer,It easy circuit and small size. Volt output = Volt Zenerdiode. Output Current 100mA (min). It easy circuit and small size. Power Supply 9VDC no transformer You may know the reason that make power supply circuit have large-sized as a result , because transformer. Way this out be [...]

120 and 240Vac LED Voltage Indicator Useful for power lines control Simple, transformerless circuitry This circuit, designed on request, has proven to be useful to indicate when the voltage in a power supply line is changing from 120V to 240Vac. It can be used in different circumstances and circuits, mainly when an increase in ac or dc supply voltage needs to [...]

12V Transformerless Power Supply This circuit will supply up to about 20ma at 12 volts. It uses capacitive reactance instead of resistance; and it doesn’t generate very much heat.The circuit draws about 30ma AC. Always use a fuse and/or a fusible resistor to be on the safe side. The values given are only a guide. There should be more [...]

DC Regulator supply 15V non transformer Friends at don’t like large-sized of a transformer. I begs for to advise 15VDC regulator power supply can give the trend current get low about 80mA not exceed. But enough will usable small-sized circuit has comfortablely. Think I uses Zener Diode be formed help maintain one’s position volt be stable , and use Transistor help [...]

Negative Volage Regulator 6V not use Transformer If friends with look for Mini power supply 6V sizes. That give negative voltage. I begs for to advise this circuit. It has prominent small-sized point and light weight. Because do not use Transformer. But still can use current get 0.07Amp not exceed and when see the circuit. Think use Zener diode control voltage be [...]

ZN414-MK484 Portable AM Receiver Apr 9, 2008 … An AM portable radio receiver made from the ZN414 IC. The ZN414 ic has now been replaced by the MK484 which is identical in performance and…..

Simple 27 MHz Receiver Feb 7, 2008 … This is a simple RF receiver mainly for low-distance digital radio receiverapplication. … AM/FM/SW Active Antenna by MPF102 …

6 Transistor Super Regen Receiver by BC548 Dec 19, 2007 … This little super-regenerative receiver is essentially an AM receiver, with “ slope detection” used for FM. By tuning to one side of the …

Simple Field strength meter Here is a handy field strength meter that can be used to check the strength of AM radio signals.The circuit is a very useful for those who assemble radio transmitters(especially in the tuning of the final stage for maximum range)….

Low cost AM radio Here is the circuit diagram of a simple and low cost AM radio. The working of this radio circuit is straight forward. Inductor L1 and capacitor C1 forms the necessary tank circuit. Diode D1 performs the job of de-modulation. Transistor T1 is wired as a preamplifier whose output is further amplified by the IC LM386…

Simple Coil-less AM receiver by LF356 This AM receiver is working perfectly without the need of coils or even a variable capacitor. The LF356 is the basic component. P1 and P2 are the frequency selectors. Use a small telescopic antenna. The stations selectivity is not perfect but is acceptable…..

AM reciever with TDA1072A This reciever uses the TDA1072A which is a complete AM reciever on a chip and it only requires comparitively few peripheral components to complete a high quality AM radio Circuit. Unlike some other AM radio ICs, a minimum number of external tuned inductors are used to preserve ….

ZN414-MK484 Portable AM Receiver An AM portable radio receiver made from the ZN414 IC. The ZN414 ic has now been replaced by the MK484 which is identical in performance and pinout. Designed around the popular ZN414 IC this receiver covers the medium wave band band from approximately 550 to 1600 KHz….

CRYSTAL RADIO Description: Crystal radio requires no power supply to operate because it uses energy from the signals it receives. Performance is – like one should expect – poor. Nevertheless, with a good antenna and proper ground, it shouldn’t be too difficult to tune to a strong AM station…..

AM portable radio receiver by ZN414 IC An AM portable radio receiver made from the ZN414 IC. The ZN414 ic has now been replaced by the MK484 which is identical in performance and pinout. Notes: Designed around the popular ZN414 IC this receiver covers the medium wave band band from approximately 550 to 1600 KHz [...]

Water Pump Relay Controller Circuit Schematic Water reservoir automatic level control Simple circuitry – 12V supply Device purpose: By means of a Relay, employed to drive a water pump, this circuit provides automatic level control of a water reservoir or well. Circuit operation: The shorter steel rod is the “water high” sensor,…

Relay Coil Energy Saver Some relays will become warm if they remain energized for some time. The circuit shown here will actuate the relay as before but then reduce the ‘hold’ current through the relay coil current by about 50%, thus considerably reducing the amount of heat dissipation and wasted power. …

Reducing Relay Power Consumption Relays are often used as electrically controlled switches. Unlike transistors, their switch contacts are electrically isolated from the control input. On the other hand, the power dissipation in a relay coil may be unattractive for battery-operated applications….

DMX Controlled Relay Kit What if you need to do more than dim a resistive incandescent light in your DMX control chain? What if you need to provide an on/off function? Just like the K8039 dimmer, if you are switching a device that doesn’t….

Boost up voltage for relay by BC558 Using relay general the majority then to use power supply that have DC Voltage with the value volt that specify on relay. For relay work but , if , we have no power supply that want to feed give relay. This circuit helps to give relay can work….

Moisture Activated Relay by Bipolar Transistor Today we try to build warn the moistness or Moisture Activated better. Or do go to use be warn it rains. Because of be the circuit is simple. Follow the circuit will think use Bipolar Transistor just one only. When measure touch the moistness make the electric current….

Relay Driver The above is a standard way of driving Small Power Relays from Control Signals generated by Logic or Opamp Circuits. C2 and R5 form a snubber which improves the life of the metal contacts, the contacts can erode due to sparking when switching inductive or even big loads…..

Temperature-Controlled Soldering Iron One reason why commercial soldering stations are expensive is that, in general, they require the use of soldering irons with inbuilt temperature sensors, such as thermocouples. This circuit eliminates the need for a special sensor because it senses the temperature of a soldering iron heating element directly from its resistance…..

Temperature controlled DC fan by BD140 Here is a simple circuit based on two transistors that can be used to control the speed of a 12 V DC fan depending on the temperature.A thermistor (R1) is used to sense the temperature. When the temperature increases the base current of Q1 (BC 547) increases which in turn decreases the collector voltage of the same transistor. Since the collector of Q1 is coupled to the base of Q2 (BD 140), ….

Arduino temperature controlled PC Fan Our buds at uC Hobby have another winnerin their Hobby Parts for Articles program: Oscar Gonzalez gives us a simple tutorial for speed controlling a PC FAN and reading a LM35 temperature sensor with an Arduino microcontroller. He covers the use of an optocoupler, PWM (Pulse Width Modulation) and….

Temperature Controlled NICD Charger by IC LM311 This circuit is for a temperature controlled constant current battery charger. It works with NICD, NIMH, and other rechargeable cells. The circuit works on the principle that most rechargeable batteries show an increase in temperature when the cells becomes fully charged. ….

Auto-Fan, automatic temperature control by 741

Temperature-Controlled Temperature-Controlled Soldering Iron. Tuesday, May 17th, 2011. One reason why commercial soldering stations are expensive is that, in general, they require …

Temperature Control Fan Temperature controlled DC fan by BD140. Tuesday, February 1st, 2011. Here is a simple circuit based on two transistors that can be used to control the speed …

Dfferential Temperature Relay Switch by IC 741 This is Circuit Dfferential Temperature Relay Switch .
Use IC 741 for control relay ad Diode D1,D2 for sencer Temperature . VR1 for adjusable voltage

Power Amp OCL 100W by Transister MJ15003,MJ15004 Jun 15, 2007 … This Circuit Power Amp OCL 100W by Transister.It old circuit,but nice circuitamplifier. Use transister MJ15003 and MJ15004, power supply …

Power Amplifier OCL 100W Mosfet J162 + K1058 Jun 27, 2007 … This is circuit MOSFET power amplifier OCL, Output 100w , use mosfet k134+j49 or Mosfet J162 + K1058 Output 112W at Speaker 8 OHM.

Power Amplifier OTL 100W by transistor 2N3055 (with PCB) May 29, 2007 … 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.

Basic MOSFET amplifier 100W with 2SK1530,2SJ201 Sep 2, 2007 … I propose you here a basic MOSFET amplifier. Output power is +/- 100 Wrms under 8 ohms or +/- 160 Wrms under 4 ohms.

100W Amplifier Oct 21, 2008 … If friend want Bipolar Transistor power Amplifier Circuit. , In model HIFI OCL100W RMS. I sizes think this circuit may is the one choice …

100W Audio Amplifier Transistor by BDW84 Jan 22, 2008 … The circuit works from a symmetrical ±40 VDC power supply and draws a maximum current of 2.6 A. The input circuit of the amplifier is a …

Bipolar Amplifier HIFI OCL 100W by BD317-BD318 Oct 21, 2008 … If friend want Bipolar Transistor power Amplifier Circuit. , In model HIFI OCL100W RMS. I sizes think this circuit may is the one choice …

Mosfet Amplifier OTL 100W by K1058,J162 Apr 30, 2008 … This includes a 220uF capacitor and two diodes to slow down the switch-on to reduce the output thump as the output capacitor charges through …

100W RMS Amplifier Jan 29, 2008 … This is a 100 watt basic power amp that was designed to be (relatively) easy to build at a reasonable cost. It has better performance (read: …