555 multivibrator like power oscillator

This is dual 555 multivibrator like power oscillator. This is my contraption and conception but couple of decades old. It appears to have errors. It worked but the document fixing after design worked, not done. This can be used to make a small inverter, for powering 230V gadgets of low power. The transformer is used in step-up mode. It may make a sound if the laminations are not of good quality.

This circuit can be modified using 7555 and switching transistors like BD139 driving a Ferrite 100 kHz transformer to build a Fluorescent Lamp of 10W to 20W.

From Schematics of delabs

Fluorescent lamps can be fired and lit at high frequency at relatively lower voltages. Experiment both with frequency and pulse width to get nominal lighting at good efficiency. One of the reasons CFL lamps -230V and emergency lamps 12V fail, is failure of the switching devices. These have to be overrated thrice or more, the switching heat dissipation should not be underestimated, during low/high voltage and keep a aging allowance.

Designing a working circuit is no big deal. But making a batch of reliable and robust power electronics products, which are idiot proof and abuse resistant is a challenge for engineering. Then they will need it at an affordable price too… Checkmate !

NE612 – Balanced mixer with Local Oscillator

I am designing a circuit that implements an AM radio circuit that ultilises the IC Double mixer and Oscillator NE612. I was just wondering whether there is any standard symbol for this kind of IC.

mail from CM


There is no standard symbol for NE612, just a square box. You have to make a custom part in the CAD software or see if someone has done that. check these links on info of NE612 circuit and symbol….

GM47: Simple 30m Band QRP CW-Transceive

The Rx mixer is followed by a IF stage featuring an NE592. The mixer’s balanced output is directly connected to the amplifier’s differential input, minimizing component count at this point.

Simple 30m Band QRP CW-Transceiver

Direct Conversion Receiver using NE612 for HF Bands

The NE612 is an integrated circuit which contains a balanced mixer with its own on-board local oscillator and voltage regulator. The mixer can provide up to 18dB of gain at 45 Mhz, and the local oscillator will operate up to 200 Mhz.

HF Transceiver using NE612

I would be working on the Transverter first, as with this, I could try out the 9Mhz SSB Module that I already have. I would be building the Transverter for the 14 Mhz band depending on the values from my DC Receiver project using the NE612 IC

delabs