PNP Boost for Positive Voltage Regulator

This is the positive voltage regulator circuit with PNP Boost transistor: The IC8211 presents the voltage reference and regulator amplifier, while Q1 will be the series pass transistor. R1 defines the output current of the IC8211, while C1 and C2 present loop stability and as well act to suppress feedthrough of input transients to the… Read More »

100W RF Amplifier with BLY94

This is a 100W RF amplifier built based on RF power transistor BLY94. Active components: BLY94 Coaxial cable length : K x Lambda / 4, where K = 0.66 for 50 ohm cable and K = 0.8 for 75 ohm cable. L1 = L6 = 2 turns / 1.5mm / 14mm L2 = L7 =… Read More »

Simple Smoke Alarm using Photo Interrupter Module

This is a really simple smoke alarm circuit design. The circuit consists of two important modules that are sensor module using a photo interrupter module and alarm module using a tone generator IC NE555 with astable multivibrator configuration and then connected to the speaker, so you can hear the alarm sound.

Vox Tone Bender Pedal

This is the circuit diagram of Vox Tone Bender Pedal. The circuit is very similar to Fuzz Face pedal. The Vox ToneBender will have a lot more treble response than the Fuzz Face…maybe to help brighten up those characteristically “dark” sounding British amps some. Using a Vox ToneBender with a Fender Twin, or any other… Read More »

Two Station Intercom based on LM386

This a two station intercom. It uses two wires to run between each intercom unit. Each is self contained with its own battery, speaker, microphone and amplifier circuit. An LM386 audio power amplifier is used. It is widely available, used a minimum of external parts and is well suited to battery operation. It will give… Read More »

Two Chips AM Radio Receiver

This two chips AM radio receiver circuit is a tuned radio frequency (TRF) receiver of the standard AM (amplitude modulation) radio with broadcast frequencies at 550kHz-600kHz. This is a simple and easy to build AM radio circuit which only using two integrated circuits (IC). This circuit works with 9V voltage supply, you could use 9V… Read More »

FM Voice Transmitter

The following diagram is the circuit diagram of voice transmitter which use FM signal carrier to transmit the vioce signal to the FM receiver device. Components List: R1 = 4.7K R2 = 330 ohm C1 = 0.001uF (1nF) C2 = 10-40pF C3 = 4.7pF Q1 = 2N3904 L1 = see text Misc = Electret mike,… Read More »

Telephone Switcher

This diagram is the schematic diagram of telephone switcher using relays. This device connects to the telephone line and can be used to remotely control up to 4 relay outputs using a DTMF (tone dialing) telephone. A number of user settings are available to improve the useability and security of the device. The kit comes… Read More »


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