3V Strobe Light Miniature

This is the circuit diagram of 3V strobe light miniature. The strobe lights are generally used to create nice looking visual effects in disco halls and auditoria. This post explain how to build the circuit of a battery operated portable miniature strobe light, using inexpensive components. For convenience and simplicity, an ordinary neon lamp is… Read More »

Home Telephone Call Recorder

This is the circuit connection of home telephone call recorder that uses very few components. In order to understand its working, we must first have the basic knowledge of standard telephone wiring and a stereo plug. In some countries, landline telephones primarily use RJ11 wiring, which has two wires—tip and ring. While tip is the… Read More »

12W Audio Amplifier based MOSFET 2SK135 / 2SJ50

This is a small 12W audio amplifier over a load of 8 Ω, that combining the NE5534 integrated with a pair of V-MOSFET transistor output stage technology as we get excellent sound performance. MOSFET 2SK135 / 2SJ50 from Hitachi is used in this circuit. Input sensitivity of the circuit is 3V RMS maximum, the distortion factor… Read More »

70W OCL Power Amplifier

This is the circuit diagram of 70W OCL power amplifier with output power of 70 watts single channel. It uses power transistor TIP2955 and TIP3055 as main component. The power supply used for this amplifier is a symmetrical / dual polarity power supply with output voltage 25V – 32V. This amplifier dan be used to… Read More »

5VDC Single Polarity to 12VDC Dual Polarity Converter

This is the circuit diagram of 5VDC single polarity to 12VDC dual polarity converter based on IC LM2595-12 from National Semiconductor. This circuit will convert 5V DC single voltage (+) become 12V DC dual polarity output (+), GND, (-).

0-60V / 0-2A Variable Power Supply

This is the circuit diagram of 0-60V / 0-2A variable power supply. Of course this circuit used to cover the voltage range from 0 to 60V and current from 0 to 2A. The maximum current can be increased, if we add the power transistors needed. Note the power output, just to cite one example, if… Read More »

7 Segment LED Digital Clock with IC MM5314N

This is the circuit diagram of digital clock based on IC MM5314N. The clock display uses 6 pieces of 7 Segment LED with format HH:MM:SS. The power supply for this circuit already included, so you can connect this circuit directly to the mains. The DC supply is about 5-12V.

LED Indicator for 220V AC Mains

This is the schematic diagram of LED indicator for 220V AC Mains which can be used to indicate that the cable lines is connected to 220v electrical installations. The current through the LED is not limited to the resistor, but the capacitance of the capacitor. The capacitance can be selected so that the current passing… Read More »


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